WorldWideScience

Sample records for control reduces instability

  1. Locomotor Adaptation Improves Balance Control, Multitasking Ability and Reduces the Metabolic Cost of Postural Instability

    Science.gov (United States)

    Bloomberg, J. J.; Peters, B. T.; Mulavara, A. P.; Brady, R. A.; Batson, C. D.; Miller, C. A.; Ploutz-Snyder, R. J.; Guined, J. R.; Buxton, R. E.; Cohen, H. S.

    2011-01-01

    During exploration-class missions, sensorimotor disturbances may lead to disruption in the ability to ambulate and perform functional tasks during the initial introduction to a novel gravitational environment following a landing on a planetary surface. The overall goal of our current project is to develop a sensorimotor adaptability training program to facilitate rapid adaptation to these environments. We have developed a unique training system comprised of a treadmill placed on a motion-base facing a virtual visual scene. It provides an unstable walking surface combined with incongruent visual flow designed to enhance sensorimotor adaptability. Greater metabolic cost incurred during balance instability means more physical work is required during adaptation to new environments possibly affecting crewmembers? ability to perform mission critical tasks during early surface operations on planetary expeditions. The goal of this study was to characterize adaptation to a discordant sensory challenge across a number of performance modalities including locomotor stability, multi-tasking ability and metabolic cost. METHODS: Subjects (n=15) walked (4.0 km/h) on a treadmill for an 8 -minute baseline walking period followed by 20-minutes of walking (4.0 km/h) with support surface motion (0.3 Hz, sinusoidal lateral motion, peak amplitude 25.4 cm) provided by the treadmill/motion-base system. Stride frequency and auditory reaction time were collected as measures of locomotor stability and multi-tasking ability, respectively. Metabolic data (VO2) were collected via a portable metabolic gas analysis system. RESULTS: At the onset of lateral support surface motion, subj ects walking on our treadmill showed an increase in stride frequency and auditory reaction time indicating initial balance and multi-tasking disturbances. During the 20-minute adaptation period, balance control and multi-tasking performance improved. Similarly, throughout the 20-minute adaptation period, VO2 gradually

  2. Longer reaction time of the fibularis longus muscle and reduced postural control in basketball players with functional ankle instability: A pilot study.

    Science.gov (United States)

    Méndez-Rebolledo, Guillermo; Guzmán-Muñoz, Eduardo; Gatica-Rojas, Valeska; Zbinden-Foncea, Hermann

    2015-08-01

    Motor control evaluation in subjects with functional ankle instability is questionable when both ankles of the same subject are compared (affected vs non-affected). To compare the postural control and reaction time of ankle muscles among: basketball players with FAI (instability group), basketball players without FAI (non-instability group) and healthy non-basketball-playing participants (control group). Case-control study. Laboratory. Instability (n = 10), non-instability (n = 10), and control groups (n = 11). Centre of pressure variables (area, velocity and sway) were measured with a force platform. Reaction time of ankle muscles was measured via electromyography. A one-way ANOVA demonstrated that there were significant differences between the instability and non-instability groups in the fibularis longus (p postural control and longer reaction time of the fibularis and tibialis anterior muscles. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Neuromuscular control and ankle instability.

    Science.gov (United States)

    Gutierrez, Gregory M; Kaminski, Thomas W; Douex, Al T

    2009-04-01

    Lateral ankle sprains (LAS) are common injuries in athletics and daily activity. Although most are resolved with conservative treatment, others develop chronic ankle instability (AI)-a condition associated with persistent pain, weakness, and instability-both mechanical (such as ligamentous laxity) and functional (neuromuscular impairment with or without mechanical laxity). The predominant theory in AI is one of articular deafferentation from the injury, affecting closed-loop (feedback/reflexive) neuromuscular control, but recent research has called that theory into question. A considerable amount of attention has been directed toward understanding the underlying causes of this pathology; however, little is known concerning the neuromuscular mechanisms behind the development of AI. The purpose of this review is to summarize the available literature on neuromuscular control in uninjured individuals and individuals with AI. Based on available research and reasonable speculation, it seems that open-loop (feedforward/anticipatory) neuromuscular control may be more important for the maintenance of dynamic joint stability than closed-loop control systems that rely primarily on proprioception. Therefore, incorporating perturbation activities into patient rehabilitation schemes may be of some benefit in enhancing these open-loop control mechanisms. Despite the amount of research conducted in this area, analysis of individuals with AI during dynamic conditions is limited. Future work should aim to evaluate dynamic perturbations in individuals with AI, as well as subjects who have a history of at least one LAS and never experienced recurrent symptoms. These potential findings may help elucidate some compensatory mechanisms, or more appropriate neuromuscular control strategies after an LAS event, thus laying the groundwork for future intervention studies that can attempt to reduce the incidence and severity of acute and chronic lateral ankle injury.

  4. Effects of reduced plantar cutaneous sensation on static postural control in individuals with and without chronic ankle instability.

    Science.gov (United States)

    Song, Kyeongtak; Kang, Tae Kyu; Wikstrom, Erik A; Jun, Hyung-Pil; Lee, Sae Yong

    2017-10-01

    The purpose of this study was to determine how reduced plantar cutaneous sensation influences static postural control in individuals with and without CAI. A case-control study design. Twenty-six individuals with self-reported CAI and 26 matched healthy controls participated in this study. The plantar aspect of the participants' foot was then submersed in ice water (0°C) for 10min to reduce plantar sensation. Before and after the cooling procedure, plantar cutaneous sensation thresholds and single leg balance with eyes open and closed were assessed. Significantly, higher scores were observed in both groups after ice water submersion (ppostural control improvement in both groups post-cooling. In single limb balance with eyes closed, Group×Intervention interactions were observed for the TTB AP mean (p=0.003) and TTB AP SD (p=0.017); indicating postural control deficits in CAI group post-cooling, but no changes in the control group. The main finding of this study was that reduced plantar cutaneous sensation induced by an ice submersion procedure caused eyes closed postural control impairments in those with CAI but not healthy controls. The present investigation demonstrated that the ability to dynamically reweight among sensory inputs to maintain postural stability appears to be diminished in CAI patients compared to healthy controls. Copyright © 2016. Published by Elsevier Ltd.

  5. Feedback control of resistive instabilities

    International Nuclear Information System (INIS)

    White, R.B.; Rutherford, P.H.; Furth, H.P.; Park, W.; Liu Chen

    1986-01-01

    Resistive instabilities are responsible for much of the global behavior and the determination of the possible domains of operation of Tokamaks. Their successful control could have definite advantages, even making available new regimes of operation. Elimination of sawtoothing might allow operation with higher currents and more peaked current profiles, with q on axis well below unity. In this work different feedback schemes are explored. Simple analytical derivations of the effects of local heating and current drive feedback are presented. Although control of modes with m ≥ 2 is fairly straighforward, the control of the m = 1 mode is more difficult because of its proximity to ideal instability. The most promising scheme utilizes high energy trapped particles

  6. Feedback control of resistive instabilities

    International Nuclear Information System (INIS)

    White, R.B.; Rutherford, P.H.; Furth, H.P.; Park, W.; Chen, L.

    1985-12-01

    Resistive instabilities are responsible for much of the global behavior and the determination of the possible domains of operation of tokamaks. Their successful control could have definite advantages, even making available new regimes of operation. Elimination of sawtoothing might allow operation with higher currents and more peaked current profiles, with q on axis well below unity. In this work different feedback schemes are explored. Simple analytical derivations of the effects of local heating and current drive feedback are presented. Although control of modes with m greater than or equal to 2 is fairly straightforward, the control of the m = 1 mode is more difficult because of its proximity to ideal instability. The most promising scheme utilizes high energy trapped particles. 20 refs., 3 figs

  7. Efficacy of tranexamic acid in reducing blood loss in posterior lumbar spine surgery for degenerative spinal stenosis with instability: a retrospective case control study

    Directory of Open Access Journals (Sweden)

    Endres Stefan

    2011-11-01

    Full Text Available Abstract Background Degenerative spinal stenosis and instability requiring multilevel spine surgery has been associated with large blood losses. Factors that affect perioperative blood loss include time of surgery, surgical procedure, patient height, combined anterior/posterior approaches, number of levels fused, blood salvage techniques, and the use of anti-fibrinolytic medications. This study was done to evaluate the efficacy of tranexamic acid in reducing blood loss in spine surgery. Methods This retrospective case control study includes 97 patients who had to undergo surgery because of degenerative lumbar spinal stenosis and instability. All operations included spinal decompression, interbody fusion and posterior instrumentation (4-5 segments. Forty-six patients received 1 g tranexamic acid intravenous, preoperative and six hours and twelve hours postoperative; 51 patients without tranexamic acid administration were evaluated as a control group. Based on the records, the intra- and postoperative blood losses were measured by evaluating the drainage and cell saver systems 6, 12 and 24 hours post operation. Additionally, hemoglobin concentration and platelet concentration were reviewed. Furthermore, the number of red cell transfusions given and complications associated with tranexamic acid were assessed. Results The postoperative hemoglobin concentration demonstrated a statistically significant difference with a p value of 0.0130 showing superiority for tranexamic acid use (tranexamic acid group: 11.08 g/dl, SD: 1.68; control group: 10.29 g/dl, SD: 1.39. The intraoperative cell saver volume and drainage volume after 24 h demonstrated a significant difference as well, which indicates a less blood loss in the tranexamic acid group than the control group. The postoperative drainage volume at12 hours showed no significant differences; nor did the platelet concentration Allogenic blood transfusion (two red cell units was needed for eight patients

  8. Systems and methods for controlling flame instability

    KAUST Repository

    Cha, Min Suk

    2016-07-21

    A system (62) for controlling flame instability comprising: a nozzle (66) coupled to a fuel supply line (70), an insulation housing (74) coupled to the nozzle, a combustor (78) coupled to the nozzle via the insulation housing, where the combustor is grounded (80), a pressure sensor (82) coupled to the combustor and configured to detect pressure in the combustor, and an instability controlling assembly coupled to the pressure sensor and to an alternating current power supply (86), where, the instability controlling assembly can control flame instability of a flame in the system based on pressure detected by the pressure sensor.

  9. Systems and methods for controlling flame instability

    KAUST Repository

    Cha, Min; Xiong, Yuan; Chung, Suk-Ho

    2016-01-01

    A system (62) for controlling flame instability comprising: a nozzle (66) coupled to a fuel supply line (70), an insulation housing (74) coupled to the nozzle, a combustor (78) coupled to the nozzle via the insulation housing, where the combustor

  10. Electroacoustic control of Rijke tube instability

    Science.gov (United States)

    Zhang, Yumin; Huang, Lixi

    2017-11-01

    Unsteady heat release coupled with pressure fluctuation triggers the thermoacoustic instability which may damage a combustion chamber severely. This study demonstrates an electroacoustic control approach of suppressing the thermoacoustic instability in a Rijke tube by altering the wall boundary condition. An electrically shunted loudspeaker driver device is connected as a side-branch to the main tube via a small aperture. Tests in an impedance tube show that this device has sound absorption coefficient up to 40% under normal incidence from 100 Hz to 400 Hz, namely over two octaves. Experimental result demonstrates that such a broadband acoustic performance can effectively eliminate the Rijke-tube instability from 94 Hz to 378 Hz (when the tube length varies from 1.8 m to 0.9 m, the first mode frequency for the former is 94 Hz and the second mode frequency for the latter is 378 Hz). Theoretical investigation reveals that the devices act as a damper draining out sound energy through a tiny hole to eliminate the instability. Finally, it is also estimated based on the experimental data that small amount of sound energy is actually absorbed when the system undergoes a transition from the unstable to stable state if the contrpaol is activated. When the system is actually stabilized, no sound is radiated so no sound energy needs to be absorbed by the control device.

  11. Control of instability in nitric acid evaporators for plutonium processing

    International Nuclear Information System (INIS)

    1998-03-01

    Improved control of the nitric acid process evaporators requires the detection of spontaneously unstable operating conditions. This process reduces the volume of contaminated liquid by evaporating nitric acid and concentrating salt residues. If a instability is identified quickly, prompt response can avert distillate contamination. An algorithm applied to the runtime data was evaluated to detect this situation. A snapshot of data from a histogram in the old process control software was captured during the unstable conditions and modeled

  12. Feedback control of coupled-bunch instabilities

    International Nuclear Information System (INIS)

    Fox, J.D.; Eisen, N.; Hindi, H.; Linscott, I.; Oxoby, G.; Sapozhnikov, L.; Serio, M.

    1993-05-01

    The next generation of synchrotron light sources and particle accelerators will require active feedback systems to control multi-bunch instabilities. Stabilizing hundreds or thousands of potentially unstable modes in these accelerator designs presents many technical challenges. Feedback systems to stabilize coupled-bunch instabilities may be understood in the frequency domain (mode-based feedback) or in the time domain (bunch-by-bunch feedback). In both approaches an external amplifier system is used to create damping fields that prevent coupled-bunch oscillations from growing without bound. The system requirements for transverse (betatron) and longitudinal (synchrotron) feedback are presented, and possible implementation options developed. Feedback system designs based on digital signal-processing techniques are described. Experimental results are shown from a synchrotron oscillation damper in the SSRL/SLAC storage ring SPEAR that uses digital signal-processing techniques

  13. Control of the vertical instability in tokamaks

    International Nuclear Information System (INIS)

    Lazarus, E.A.; Lister, J.B.; Neilson, G.H.

    1989-05-01

    The problem of control of the vertical instability is formulated for a massless filamentary plasma. The massless approximation is justified by an examination of the role of inertia in the control problem. The system is solved using Laplace transform techniques. The linear system is studied to determine the stability boundaries. It is found that the system can be stabilized up to a critical decay index, which is predominantly a function of the geometry of the passive stabilizing shell. A second, smaller critical index, which is a function of the geometry of the control coils, determines the limit of stability in the absence of derivative gain in the control circuit. The system is also studied numerically in order to incorporate the non-linear effects of power supply dynamics. The power supply bandwidth requirement is determined by the open-loop growth rate of the instability. The system is studied for a number of control coil options which are available on the DIII-D tokamak. It is found that many of the coils will not provide adequate stabilization and that the use of inboard coils is advantageous in stabilizing the system up to the critical index. Experiments carried out on DIII-D confirm the appropriateness of the model. Using the results of the model study, we have stabilized DIII-D plasmas with decay indices up to 98% of the critical index. Measurement of the plasma vertical position is also discussed. (author) 27 figs., 6 refs

  14. Feedback control of vertical instability in TNS

    International Nuclear Information System (INIS)

    Frantz, E.R.

    1978-05-01

    Due to the unfavorable curvature of the vertical vacuum magnetic field, elongated plasmas are vertically unstable when the elongation, epsilon, becomes too large. The TNS (The Next Step) tokamak, as evolved in the Westinghouse-ORNL studies has an inside-D configuration (epsilon = 1.6, A = 5/1.25 = 4) characterized by an average decay index n approximately equal -0.75 at the plasma flux surface near the magnetic axis and is vertically unstable with a growth rate γ 0 approximately 10 5 sec -1 . Eddy currents produced in the vacuum vessel wall will slow this instability to growth rates γ 0 approximately 10 2 sec -1 provided there are no transverse insulating gaps in the vessel wall. A matrix equation has been developed for calculating the eddy currents induced in the EF coils and their stabilizing effect. Control theory for feedback systems with and without delay time is presented and possible plasma position detectors are discussed. For a plasma current of 6.1 MA, the controller peak power requirements using separate controller circuits are approximately 1 MW depending upon EF coil configurations and time delay. This feedback system is designed to stabilize a maximum plasma excursion of 10 cm from the midplane with delay times up to 2 sec

  15. Strategies for the control of parametric instability in advanced gravitational wave detectors

    International Nuclear Information System (INIS)

    Ju, L; Blair, D G; Zhao, C; Gras, S; Zhang, Z; Barriga, P; Miao, H; Fan, Y; Merrill, L

    2009-01-01

    Parametric instabilities have been predicted to occur in all advanced high optical power gravitational wave detectors. In this paper we review the problem of parametric instabilities, summarize the latest findings and assess various schemes proposed for their control. We show that non-resonant passive damping of test masses reduces parametric instability but has a noise penalty, and fails to suppress the Q-factor of many modes. Resonant passive damping is shown to have significant advantages but requires detailed modeling. An optical feedback mode suppression interferometer is proposed which is capable of suppressing all instabilities but requires experimental development.

  16. Strategies for the control of parametric instability in advanced gravitational wave detectors

    Energy Technology Data Exchange (ETDEWEB)

    Ju, L; Blair, D G; Zhao, C; Gras, S; Zhang, Z; Barriga, P; Miao, H; Fan, Y; Merrill, L, E-mail: juli@physics.uwa.edu.a [School of Physics, University of Western Australia, 35 Stirling Highway, Crawley, Perth, WA 6009 (Australia)

    2009-01-07

    Parametric instabilities have been predicted to occur in all advanced high optical power gravitational wave detectors. In this paper we review the problem of parametric instabilities, summarize the latest findings and assess various schemes proposed for their control. We show that non-resonant passive damping of test masses reduces parametric instability but has a noise penalty, and fails to suppress the Q-factor of many modes. Resonant passive damping is shown to have significant advantages but requires detailed modeling. An optical feedback mode suppression interferometer is proposed which is capable of suppressing all instabilities but requires experimental development.

  17. Closed loop control of the sawtooth instability in nuclear fusion

    NARCIS (Netherlands)

    Witvoet, G.; Steinbuch, M.; Westerhof, E.; Doelman, N.J.; Baar, de M.R.

    2010-01-01

    In nuclear fusion the sawtooth instability is an important plasma phenomenon, having both positive and negative effects on the tokamak plasma. Control of its period is essential in future nuclear fusion reactors. This paper presents a control oriented model of the sawtooth instability, with current

  18. Bangbang controller design and implementation for EAST vertical instability control

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yuehang, E-mail: wagn8901@mail.ustc.edu.cn [University of Science and Technology of China, Hefei (China); Xiao, Bingjia, E-mail: bjxiao@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei (China); University of Science and Technology of China, Hefei (China); Liu, Lei, E-mail: liulei@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei (China); Yuan, Qiping, E-mail: qpyuan@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei (China)

    2016-11-15

    Highlights: • The linearized plasma vertical response model is designed and analysed. • The Bangbang controller for EAST vertical displacement is designed. • The Bangbang controller is optimized for time delay of control system. • We investigate efficacy of Bangbang controller with simulations. • Performance of the controller is roughly given by experiments. - Abstract: In the EAST 2014 campaign, a new internal coil (IC) power supply was used in order to enhance the control over the plasma’s vertical instabilities. The IC power supply now allows for current and voltage working modes with much higher peak voltages and currents and faster response time. In comparison the previous power supply only allowed for the current mode. A Bangbang and PID composite controller has been designed for the voltage mode based on optimal control theory and the RZIP rigid plasma response model. This paper will demonstrate that faster and enhanced controllability are realized with the combination of Bangbang and PID controller. For the large z position drift, the Bangbang controller will export the maximum voltage to achieve much faster power supply response and slow the vertical displacement events (VDEs). The PID controller is used for the small z drifts which will finally stabilize the VDEs with minimum z position oscillation. Furthermore, to evaluate the time latency of this control system and power supply, the stability and performance of the closed loop were simulated and analysed. This controller was finally implementation and test on EAST using the Quasi-snowflake shape which achieved growth rates of 500 s{sup −1}. This paper shows that the new power supply using the bangbang + PID controller can significantly enhance the control over vertical instabilities.

  19. Reduced Order Modeling of Combustion Instability in a Gas Turbine Model Combustor

    Science.gov (United States)

    Arnold-Medabalimi, Nicholas; Huang, Cheng; Duraisamy, Karthik

    2017-11-01

    Hydrocarbon fuel based propulsion systems are expected to remain relevant in aerospace vehicles for the foreseeable future. Design of these devices is complicated by combustion instabilities. The capability to model and predict these effects at reduced computational cost is a requirement for both design and control of these devices. This work focuses on computational studies on a dual swirl model gas turbine combustor in the context of reduced order model development. Full fidelity simulations are performed utilizing URANS and Hybrid RANS-LES with finite rate chemistry. Following this, data decomposition techniques are used to extract a reduced basis representation of the unsteady flow field. These bases are first used to identify sensor locations to guide experimental interrogations and controller feedback. Following this, initial results on developing a control-oriented reduced order model (ROM) will be presented. The capability of the ROM will be further assessed based on different operating conditions and geometric configurations.

  20. Control of transversal instabilities in reaction-diffusion systems

    Science.gov (United States)

    Totz, Sonja; Löber, Jakob; Totz, Jan Frederik; Engel, Harald

    2018-05-01

    In two-dimensional reaction-diffusion systems, local curvature perturbations on traveling waves are typically damped out and vanish. However, if the inhibitor diffuses much faster than the activator, transversal instabilities can arise, leading from flat to folded, spatio-temporally modulated waves and to spreading spiral turbulence. Here, we propose a scheme to induce or inhibit these instabilities via a spatio-temporal feedback loop. In a piecewise-linear version of the FitzHugh–Nagumo model, transversal instabilities and spiral turbulence in the uncontrolled system are shown to be suppressed in the presence of control, thereby stabilizing plane wave propagation. Conversely, in numerical simulations with the modified Oregonator model for the photosensitive Belousov–Zhabotinsky reaction, which does not exhibit transversal instabilities on its own, we demonstrate the feasibility of inducing transversal instabilities and study the emerging wave patterns in a well-controlled manner.

  1. Control of Coherent Instabilities by Linear Coupling

    CERN Document Server

    Cappi, R; Möhl, D

    2001-01-01

    One of the main challenges in the design of high-energy colliders is the very high luminosity necessary to provide significant event rates. This imposes strong constraints to achieve and preserve beams of high brightness, i.e. intensity to emittance ratio, all along the injector chain. Amongst the phenomena that can blow up and even destroy the beam are transverse coherent instabilities. Two methods are widely used to damp these instabilities. The first one is Landau damping by non-linearities. The second consists in using an electronic feedback system. However, non-linearities are harmful to single-particle motion due to resonance phenomena, and powerful wideband feedback systems are expensive. It is shown in this paper that linear coupling is a further method that can be used to damp transverse coherent instabilities. The theory of collective motion is outlined, including the coupling of instability rise and damping rates, chromaticity and Landau damping. Experimental results obtained at the CERN PS are rep...

  2. Controlling chaos in the current-driven ion acoustic instability

    International Nuclear Information System (INIS)

    Fukuyama, T.; Taniguchi, K.; Kawai, Y.

    2002-01-01

    Control of intermittent chaos caused by the current-driven ion acoustic instability is attempted and the controlling mechanism is investigated. When a small negative dc voltage is applied to the chaotic system as a perturbation, the system changes from a chaotic state to a periodic state while maintaining the instability, indicating that the chaotic state caused by the ion acoustic instability is well controlled by applying a small negative dc voltage. A hysteresis structure is observed on the V-I curve of the mesh grid to which the negative dc voltage to control is applied. Furthermore, when a negative dc voltage is applied to the state which shows a laminar structure existing under same experimental conditions, the system becomes chaotic via a bifurcation. Driven-chaos is excited when a negative dc voltage is applied to the laminar state. Applying a small negative dc voltage leads to controlling intermittent chaos while exciting driven-chaos

  3. International Conference on Instability and Control of Massively Separated Flows

    CERN Document Server

    Soria, Julio

    2015-01-01

    This book contains the outcome of the international meeting on instability, control and noise generated by massive flow separation that was organized at the Monash Center, in Prato, Italy, September 4-6, 2013. The meeting served as the final review of the EU-FP7 Instability and Control of Massively Separated Flows Marie Curie travel grant and was supported by the European Office of Aerospace Research and Development. Fifty leading specialists from twelve countries reviewed the progress made since the 50s of the last century and discussed modern analysis techniques, advanced experimental flow diagnostics, and recent developments in active flow control techniques from the incompressible to the hypersonic regime. Applications involving massive flow separation and associated instability and noise generation mechanisms of interest to the aeronautical, naval and automotive industries have been addressed from a theoretical, numerical or experimental point of view, making this book a unique source containing the stat...

  4. Reducing Harmonic Instability and Resonance Problems in PMSG Based Wind Farms

    DEFF Research Database (Denmark)

    Ebrahimzadeh, Esmaeil; Blaabjerg, Frede; Wang, Xiongfei

    2018-01-01

    Unlike conventional power systems where harmonic resonances are coming from passive inductive and capacitive elements, large-scale power electronic systems like wind farms present a more complex system, where the fast dynamics of the power electronic converters may present an inductive or capacit......Unlike conventional power systems where harmonic resonances are coming from passive inductive and capacitive elements, large-scale power electronic systems like wind farms present a more complex system, where the fast dynamics of the power electronic converters may present an inductive...... or capacitive behavior. Therefore, the interactions between the fast controllers of the power converters and the passive elements may lead to harmonic instability and new resonances at various frequencies. This paper presents an optimum design technique for the Wind Turbine (WT) inner controllers in a PMSG...... based wind farm in order to reduce the number of resonances and to mitigate harmonic instability. In the approach, a PMSG based wind farm is modeled as a Multi-Input Multi-Output (MIMO) dynamic system by modeling the high bandwidth control loops of the power converters. Resonance frequencies...

  5. Control of thermoacoustic instability with a drum-like silencer

    Science.gov (United States)

    Zhang, Guangyu; Wang, Xiaoyu; Li, Lei; Jing, Xiaodong; Sun, Xiaofeng

    2017-10-01

    Theoretical investigation is carried out by a novel method of controlling thermoacoustic instability with a drum-like silencer. It is shown that by decreasing the frequency of thermoacoustic system, the instability can be suppressed with the help of drum-like silencer. The purely reactive silencer, which is composed of a flexible membrane and a backing cavity, is usually known as a noise control device that works effectively in low frequency bandwidth without any aerodynamic loss. In present research, the silencer is exploited in a Rijke tube, as a means of decreasing the natural frequency of the system, and consequently changing the resonance period of the system. The "transfer element method" (TEM) is used to consider the interactions between the acoustic waves and the flexible membranes of the silencer. The effects of all possible properties of the silencer on the growth rate and resonance frequency of the thermoacoustic system are explored. According to the calculation results, it is found that for some properties of the silencer, the resonance frequencies are greatly decreased and then the phase difference between the unsteady heat release and the pressure fluctuation is increased. Consequently, the instability is suppressed with some dissipation that can not be able to control its onset in the original system. Therefore, when the damping is low, but not zero, it is effective to control thermoacoustic instability with this technique.

  6. The plastic instability of clamped-clamped conical thin-walled pipe reducers

    International Nuclear Information System (INIS)

    Awad, Ibrahim; Saleh, Ch.A.R.; Ragab, A.R.

    2016-01-01

    The analytical study for plastic deformation of clamped–clamped conical reducer pipe under internal pressure does not deduce a closed form expression for the pressure at plastic instability. The presented study employs finite element analysis (FEA) to estimate the internal pressure at instability for conical reducers made of different materials and having different dimensional configurations. Forty dimensional configurations, classified as medium type, and five types of materials have been included in the analysis using ABAQUS package. A correlation expression is derived by nonlinear regression to predict the instability pressure. The proposed expression is verified for other dimensional configurations out of the above used forty models and for other materials. Experiments have been conducted by pressurizing conical clamped-clamped reducers until bursting in order to verify the finite element models. Comparison of instability pressures, strains and deflections at specific points along the conical surface shows satisfactory agreement between analysis and experiments. - Highlights: • This study offers a parametric study of the plastic instability pressure of clamped-clamped conical reducers. • A closed form analytical expression for the instability pressure is derived by using nonlinear regression. • The finite element analysis is validated by conducting bursting tests.

  7. Slag Evaluation to Reduce Energy Consumption and EAF Electrical Instability

    OpenAIRE

    Vieira,Deisi; Almeida,Rodolfo Arnaldo Montecinos de; Bielefeldt,Wagner Viana; Vilela,Antônio Cezar Faria

    2016-01-01

    In steel mills that operate with electric arc furnaces (EAF), it is interesting to ensure greater stability to the electric arc to aim at less distortion in the electrical system, with consequent reduction in electric power consumption. The slag foaming increases electric arc stability by reducing the total harmonic distortion (THD) between EAF phases. In this study, information about the chemical composition of the slag and electrical parameters of an EAF were collected. With the composition...

  8. Multimaterial Control of Instability in Soft Mechanical Metamaterials

    Science.gov (United States)

    Janbaz, Shahram; McGuinness, Molly; Zadpoor, Amir A.

    2018-06-01

    Soft mechanical metamaterials working on the basis of instability have numerous potential applications in the context of "machine materials." Controlling the onset of instability is usually required when rationally designing such metamaterials. We study the isolated and modulated effects of geometrical design and material distribution on the onset of instability in multimaterial cellular metamaterials. We use multimaterial additive manufacturing to fabricate cellular specimens whose unit cells are divided into void space, a square element, and an intermediate ligament. The ratio of the elastic modulus of the ligament to that of the square element [(EL)/(ES)] is changed by using different material types. Computational models are also developed, validated against experimental observations, and used to study a wide range of possible designs. The critical stress can be adjusted independently from the critical strain by changing the material type while keeping [(EL)/(ES)] constant. The critical strain shows a power-law relationship with [(EL)/(ES)] within the range [(EL)/(ES)]=0.1 - 10 . The void shape design alters the critical strain by up to threefold, while the combined effects of the void shape and material distribution cause up to a ninefold change in the critical strain. Our findings highlight the strong influence of material distribution on the onset of the instability and buckling mode.

  9. Effects of joint mobilization on chronic ankle instability: a randomized controlled trial.

    Science.gov (United States)

    Cruz-Díaz, David; Lomas Vega, Rafael; Osuna-Pérez, Maria Catalina; Hita-Contreras, Fidel; Martínez-Amat, Antonio

    2015-01-01

    To evaluate the effects of joint mobilization, in which movement is applied to the ankle's dorsiflexion range of motion, on dynamic postural control and on the self-reported instability of patients with chronic ankle instability (CAI). A double-blind, placebo-controlled, randomized trial with repeated measures and a follow-up period. Ninety patients with a history of recurrent ankle sprain, self-reported instability, and a limited dorsiflexion range of motion, were randomly assigned to either the intervention group (Joint Mobilizations, 3 weeks, two sessions per week) the placebo group (Sham Mobilizations, same duration as joint mobilization) or the control group, with a 6 months follow-up. Dorsiflexion Range of Motion (DFROM), Star Excursion Balance Test (SEBT) and CAI Tool (CAIT) were outcome measures. A separate 3 × 4 mixed model analysis of variance was performed to examine the effect of treatment conditions and time, and intention-to-treat (ITT) analysis was applied to evaluate the effect of the independent variable. The application of joint mobilization resulted in better scores of DFROM, CAIT, and SEBTs in the intervention group when compared with the placebo or the control groups (p ankle DFROM, postural control, and self-reported instability. These results suggest that joint mobilization could be applied to patients with recurrent ankle sprain to help restore their functional stability. Implications for Rehabilitation Functional instability is a very common sequela in patients with CAI, resulting in reduced quality of living due to the limitations it imposes on daily life activities. The mobilization with movement technique presented by Mulligan, and based on the joint mobilization accompanied by active movement, appears as a valuable tool to be employed by physical therapists to restore ankle function after a recurrent ankle sprain history. ROM restriction, subjective feeling of instability and dynamic postural control are benefiting from the joint

  10. Combustion instability control in the model of combustion chamber

    International Nuclear Information System (INIS)

    Akhmadullin, A N; Ahmethanov, E N; Iovleva, O V; Mitrofanov, G A

    2013-01-01

    An experimental study of the influence of external periodic perturbations on the instability of the combustion chamber in a pulsating combustion. As an external periodic disturbances were used sound waves emitted by the electrodynamics. The purpose of the study was to determine the possibility of using the method of external periodic perturbation to control the combustion instability. The study was conducted on a specially created model of the combustion chamber with a swirl burner in the frequency range from 100 to 1400 Hz. The study found that the method of external periodic perturbations may be used to control combustion instability. Depending on the frequency of the external periodic perturbation is observed as an increase and decrease in the amplitude of the oscillations in the combustion chamber. These effects are due to the mechanisms of synchronous and asynchronous action. External periodic disturbance generated in the path feeding the gaseous fuel, showing the high efficiency of the method of management in terms of energy costs. Power required to initiate periodic disturbances (50 W) is significantly smaller than the thermal capacity of the combustion chamber (100 kW)

  11. Active control of magneto-hydrodynamic instabilities in hot plasmas

    CERN Document Server

    2015-01-01

    During the past century, world-wide energy consumption has risen dramatically, which leads to a quest for new energy sources. Fusion of hydrogen atoms in hot plasmas is an attractive approach to solve the energy problem, with abundant fuel, inherent safety and no long-lived radioactivity.  However, one of the limits on plasma performance is due to the various classes of magneto-hydrodynamic instabilities that may occur. The physics and control of these instabilities in modern magnetic confinement fusion devices is the subject of this book. Written by foremost experts, the contributions will provide valuable reference and up-to-date research reviews for "old hands" and newcomers alike.

  12. Feedback Control Of Dynamical Instabilities In Classical Lasers And Fels

    CERN Document Server

    Bielawski, S; Szwaj, C

    2005-01-01

    Dynamical instabilities lead to unwanted full-scale power oscillations in many classical lasers and FEL oscillators. For a long time, applications requiring stable operation were typically performed by working outside the problematic parameter regions. A breakthrough occurred in the nineties [1], when emphasis was made on the practical importance of unstable states (stationary or periodic) that coexist with unwanted oscillatory states. Indeed, although not observable in usual experiments, unstable states can be stabilized, using a feedback control involving arbitrarily small perturbations of a parameter. This observation stimulated a set of works leading to successful suppression of dynamical instabilities (initially chaos) in lasers, sometimes with surprisingly simple feedback devices [2]. We will review a set of key results, including in particular the recent works on the stabilization of mode-locked lasers, and of the super-ACO, ELETTRA and UVSOR FELs [3].

  13. Using evaporation to control capillary instabilities in micro-systems.

    Science.gov (United States)

    Ledesma-Aguilar, Rodrigo; Laghezza, Gianluca; Yeomans, Julia M; Vella, Dominic

    2017-12-06

    The instabilities of fluid interfaces represent both a limitation and an opportunity for the fabrication of small-scale devices. Just as non-uniform capillary pressures can destroy micro-electrical mechanical systems (MEMS), so they can guide the assembly of novel solid and fluid structures. In many such applications the interface appears during an evaporation process and is therefore only present temporarily. It is commonly assumed that this evaporation simply guides the interface through a sequence of equilibrium configurations, and that the rate of evaporation only sets the timescale of this sequence. Here, we use Lattice-Boltzmann simulations and a theoretical analysis to show that, in fact, the rate of evaporation can be a factor in determining the onset and form of dynamical capillary instabilities. Our results shed light on the role of evaporation in previous experiments, and open the possibility of exploiting diffusive mass transfer to directly control capillary flows in MEMS applications.

  14. Control and Protection Cooperation Strategy for Voltage Instability

    DEFF Research Database (Denmark)

    Liu, Zhou; Chen, Zhe; Sun, Haishun

    2012-01-01

    Most cascaded blackouts are caused by unexpected backup relay operations due to low voltage or overload state caused by post fault load restoration dynamics. If such state can be sensed and adjusted appropriately prior to those relay actions, system stability might be sustained. This paper proposed...... a control and protection cooperation strategy to prevent post fault voltage instability. The multi-agent technology is applied for the strategy implementation; the criteria based on wide area measured apparent impedances are defined to choose the control strategy, such as tap changer adjusting or load...

  15. Active control of combustion instabilities in low NO{sub x} gas turbines

    Energy Technology Data Exchange (ETDEWEB)

    Zinn, B.T.; Neumeier, Y. [Georgia Institute of Technology, Atlanta, GA (United States)

    1995-10-01

    This 3-year research program was initiated in September, 1995, to investigate active control of detrimental combustion instabilities in low NO{sub x} gas turbines (LNGT), which burn natural gas in a lean premixed mode to reduce NO{sub x} emissions. The program will investigate the mechanisms that drive these instabilities. Furthermore, it will study active control systems (ACS) that can effectively prevent the onset of such instabilities and/or reduce their amplitudes to acceptable levels. An understanding of the driving mechanisms will not only guide the development of effective ACS for LNGT but may also lead to combustor design changes (i.e., passive control) that will fully or partially resolve the problem. Initial attempts to stabilize combustors (i.e., chemical rockets) by ACS were reported more than 40 years ago, but were unsuccessful due to lack of adequate sensors, electronics, and actuators for performing the needed control actions. Progress made in recent years in sensor and actuator technology, electronics, and control theory has rekindled interest in developing ACS for unstable combustors. While initial efforts in this area, which focused on active control of instabilities in air breathing combustors, have demonstrated the considerable potential of active control, they have also indicated that more effective observers, controllers, and actuators are needed for practical applications. Considerable progress has been made in the observer and actuator areas by the principal investigators of this program during the past 2 years under an AFOSR program. The developed observer is based upon wavelets theory, and can identify the amplitudes, frequencies, and phases of the five most dominant combustor modes in (virtually) real time. The developed actuator is a fuel injector that uses a novel magneto-strictive material to modulate the fuel flow rate into the combustor.

  16. Localized modelling and feedback control of linear instabilities in 2-D wall bounded shear flows

    Science.gov (United States)

    Tol, Henry; Kotsonis, Marios; de Visser, Coen

    2016-11-01

    A new approach is presented for control of instabilities in 2-D wall bounded shear flows described by the linearized Navier-Stokes equations (LNSE). The control design accounts both for spatially localized actuators/sensors and the dominant perturbation dynamics in an optimal control framework. An inflow disturbance model is proposed for streamwise instabilities that drive laminar-turbulent transition. The perturbation modes that contribute to the transition process can be selected and are included in the control design. A reduced order model is derived from the LNSE that captures the input-output behavior and the dominant perturbation dynamics. This model is used to design an optimal controller for suppressing the instability growth. A 2-D channel flow and a 2-D boundary layer flow over a flat plate are considered as application cases. Disturbances are generated upstream of the control domain and the resulting flow perturbations are estimated/controlled using wall shear measurements and localized unsteady blowing and suction at the wall. It will be shown that the controller is able to cancel the perturbations and is robust to unmodelled disturbances.

  17. Analysis of flow instability in steam turbine control valves

    International Nuclear Information System (INIS)

    Pluviose, M.

    1981-01-01

    With the sponsorship of Electricite de France and the French steam turbine manufacturers, the Gas Turbine Laboratory of CETIM has started a research about the unsteady phenomena of flow in control valves of steam turbines. The existence of unsteady embossment in the valve cone at rise has been as certained, and a conventional computing procedure has been applied to locate the shock waves in the valve. These shock waves may suddenly arise at some valve lifts and give way to fluttering. Valve geometries attenuating instability of flow and increasing therefore the reliability of such equipment are proposed [fr

  18. ASPEN: A fully kinetic, reduced-description particle-in-cell model for simulating parametric instabilities

    International Nuclear Information System (INIS)

    Vu, H.X.; Bezzerides, B.; DuBois, D.F.

    1999-01-01

    A fully kinetic, reduced-description particle-in-cell (RPIC) model is presented in which deviations from quasineutrality, electron and ion kinetic effects, and nonlinear interactions between low-frequency and high-frequency parametric instabilities are modeled correctly. The model is based on a reduced description where the electromagnetic field is represented by three separate temporal envelopes in order to model parametric instabilities with low-frequency and high-frequency daughter waves. Because temporal envelope approximations are invoked, the simulation can be performed on the electron time scale instead of the time scale of the light waves. The electrons and ions are represented by discrete finite-size particles, permitting electron and ion kinetic effects to be modeled properly. The Poisson equation is utilized to ensure that space-charge effects are included. The RPIC model is fully three dimensional and has been implemented in two dimensions on the Accelerated Strategic Computing Initiative (ASCI) parallel computer at Los Alamos National Laboratory, and the resulting simulation code has been named ASPEN. The authors believe this code is the first particle-in-cell code capable of simulating the interaction between low-frequency and high-frequency parametric instabilities in multiple dimensions. Test simulations of stimulated Raman scattering, stimulated Brillouin scattering, and Langmuir decay instability are presented

  19. Robust adaptive control of the sawtooth instability in nuclear fusion

    NARCIS (Netherlands)

    Bolder, J.J.; Witvoet, G.; Baar, de M.R.; Wouw, van de N.; Haring, M.A.M.; Westerhof, E.; Doelman, N.J.; Steinbuch, M.

    2012-01-01

    The sawtooth instability is a repetitive phenomenon occurring in plasmas of tokamak nuclear fusion reactors. Experimental studies of these instabilities and the effect they have on the plasma (notably the drive of secondary instabilities and consequent performance reduction) for a wide variety of

  20. Control of tropical instability waves in the Pacific

    Science.gov (United States)

    Allen, M. R.; Lawrence, S. P.; Murray, M. J.; Mutlow, C. T.; Stockdale, T. N.; Llewellyn-Jones, D. T.; Anderson, D. L. T.

    Westward-propagating waves with periods of 20-30 days and wavelengths of ˜ 1,100km are a prominent feature of sea-surface temperatures (SSTs) in the equatorial Pacific and Atlantic Oceans. They have been attributed to instabilities due to current shear. We compare SST observations from the spaceborne Along Track Scanning Radiometer (ATSR) and TOGA-TAO moored buoys with SSTs from a model of the tropical Pacific forced with observed daily windstress data. The phases of the strongest “Tropical Instability Waves” (TIWs) in the model are in closer correspondence with those observed than we would expect if these waves simply developed from infinitesimal disturbances (in which case their phases would be arbitrary). If we filter out the intraseasonal component of the windstress, all phase-correspondence is lost. We conclude that the phases of these waves are not arbitrary, but partially determined by the intraseasonal winds. The subsurface evolution of the model suggests a possible control mechanism is through interaction with remotely-forced subsurface Kelvin and Rossby waves. This is supported by an experiment which shows how zonal wind bursts in the west Pacific can modify the TIW field, but other mechanisms, such as local feedbacks, are also possible.

  1. Modeling of active control of external magnetohydrodynamic instabilities

    International Nuclear Information System (INIS)

    Bialek, James; Boozer, Allen H.; Mauel, M.E.; Navratil, G.A.

    2001-01-01

    A general circuit formulation of resistive wall mode (RWM) feedback stabilization developed by Boozer [Phys. Plasmas 5, 3350 (1998)] has been used as the basis for the VALEN computer code that calculates the performance of an active control system in arbitrary geometry. The code uses a finite element representation of a thin shell structure in an integral formulation to model arbitrary conducting walls. This is combined with a circuit representation of stable and unstable plasma modes. Benchmark comparisons of VALEN results with large aspect ratio analytic model of the current driven kink mode are in very good agreement. VALEN also models arbitrary sensors, control coils, and the feedback logic connecting these sensors and control coils to provide a complete simulation capability for feedback control of plasma instabilities. VALEN modeling is in good agreement with experimental results on DIII-D [Garofalo et al., Nucl. Fusion 40, 1491 (2000)] and HBT-EP [Cates et al., Phys. Plasmas 7, 3133 (2000)]. VALEN feedback simulations have also been used to evaluate and optimize the sensor/coil configurations for present and planned RWM experiments on DIII-D. These studies have shown a clear advantage for the use of local poloidal field sensors driving a 'mode control' feedback logic control loop and configurations which minimize the control coil coupling to the stabilizing resistive wall

  2. Impact of drag reducing polymers on the onset of instability in a pipe with reverse flow

    Science.gov (United States)

    Shashank, H. J.; Sreenivas, K. R.

    2014-11-01

    The objective of this study is to understand the mechanism by which drag reducing polymer (DRP) additives modify turbulent flow, so as to reduce turbulent drag. Reverse flow in a pipe occurs when the fluid close to the wall moves in an opposite direction to that of the core fluid. Reverse flow is established by using a piston-cylinder mechanism, the programmed motion of which imparts a known impulse to the fluid. When the piston is stopped at the end of the stroke, fluid inertia makes the core of the flow to continue in the same direction. In order to conserve mass, reverse flow is established close to the wall. An inflection point is thus formed, leading to flow instability above a critical Reynolds number. Dye and streak flow visualization experiments are performed to highlight the impact of DRP additives (polyethylene oxide, PEO, dissolved in water). The time of onset of the instability and the wavelength of the observed instability are studied in systems with and without DRP additives. This study will provide further insight into the phenomenon of turbulent polymer drag reduction.

  3. Control oriented system analysis and feedback control of a numerical sawtooth instability model

    NARCIS (Netherlands)

    Witvoet, G.; Westerhof, E.; Steinbuch, M.; Baar, de M.R.; Doelman, N.J.; Prater, R.

    2010-01-01

    A combined Porcelli-Kadomtsev numerical sawtooth instability model is analyzed using control oriented identification techniques. The resulting discrete time linear models describe the system’s behavior from crash to crash and is used in the design of a simple discrete time feedback controller, which

  4. Experimental study on thermo-hydraulic instability on reduced-moderation natural circulation BWR concept

    International Nuclear Information System (INIS)

    Watanabe, Noriyuki; Subki, M.H.; Kikura, Hiroshige; Aritomi, Masanori

    2003-01-01

    Reduced-moderation natural circulation BWR has been promoted to solve the recent challenges in BWR nuclear power technology problems as one of advanced small and medium-sized reactors equipped with the passive safety features in conformity with the natural law. However, the elimination of recirculation pumps and a high-density core due to the increase of conversion ratio could cause various thermo-hydraulic instabilities especially during the start-up stage. The occurrences of the thermo-hydraulic instabilities are not desirable and it is one of the main challenges in establishing reduced-moderation natural circulation BWR as a commercial reactor. The purpose of this present study is to experimentally investigate the driving mechanism of the thermo-hydraulic instabilities and the effect of system pressure on the unstable flow patterns. Hence, as the fundamental research for this study, a natural circulation loop that carries boiling fluid with parallel boiling channel has been constructed. Channel gap that has been set at 2 mm in order to simulate reduced-moderation reactor core. Pressure ranges of 0.1 up to 0.7 MPa, input heat flux range of 0 ou to 577 kW/m 2 , and inlet subcooling temperatures of 5, 10, and 15 K respectively, are imposed in the experiments. This experiment clarifies that changes in unstable flow patterns with increase in heat flux can be classified into two in response to system pressure range. In case of atmospheric pressure, unstable flow patters has been classified in beyond order, (1) in-phase geysering, (2) transition oscillation combined with both features of in-phase geysering and natural circulation oscillation, (3) natural circulation oscillation induced by hydrostatic head fluctuation, (4) density wave oscillation, and finally (5) stable boiling two-phase flow. On the other hand, in the system pressure range from 0.2 to 0.7 MPa, unstable patters have been dramatically changed in the following order (1) out-of-phase geysering, (2

  5. Control oriented modeling and simulation of the sawtooth instability in nuclear fusion tokamak plasmas

    NARCIS (Netherlands)

    Witvoet, G.; Westerhof, E.; Steinbuch, M.; Doelman, N.J.; Baar, de M.R.

    2009-01-01

    Tokamak plasmas in nuclear fusion are subject to various instabilities. A clear example is the sawtooth instability, which has both positive and negative effects on the plasma. To optimize between these effects control of the sawtooth period is necessary. This paper presents a simple control

  6. Familial colorectal cancer, can it be identified by microsatellite instability and chromosomal instability? - A case-control study

    DEFF Research Database (Denmark)

    Sunde, Lone; Bisgaard, Marie Luise; Soll-Johanning, Helle

    2009-01-01

    (Chromosome INstability=LOH (loss of heterozygosity) and/or DNA-aneuploidy (abnormal nuclear DNA contents)) could be used as predictors of familial CRC. Formalin-fixed tissue from 97 patients with CRC (29 patients with 2 or more affected first-degree relatives (="cases"), 29 matched CRC controls without......Colonoscopy is recommended for persons with a familial risk of colorectal cancer (CRC). A familial risk is identified by a family history with CRC and/or predisposing mutation(s). However, such information may not be available. We analysed whether MSI (MicroSatellite Instability) and/or CIN...... a family history, and 39 relatives to cases) were analysed for MSI and CIN. In this small case-control study, no significant differences in the frequencies of MSI and CIN were observed between cases with a family history and their controls without a family history. MSI+;CIN- was observed in 6/29 cases...

  7. Improved Design of PECS to reduce Flow Instability for EU-APR1400

    International Nuclear Information System (INIS)

    Hwang, Do Hyun; Lee, Keunsung

    2014-01-01

    For EU-APR1400, PECS (Passive Ex-vessel corium retaining and Cooling System), so-called core catcher, was adopted to keep the integrity of basemat in containment by preventing MCCI (Molten Core Concrete Interaction) through retaining core debris and cooling corium outside the reactor vessel. In this paper, the improved design of PECS is presented to increase coolability by reducing flow instability in the region of cooling channel. In this paper, flow instability analysis was carried out using CFD code to find out the most improved design of PECS, which is to increase coolability by reducing bubble entrainment in the region of cooling channel. The reduction of bubble entrainment in the downcomer facilitates higher mass flow rates in the downcomer. Among presented four designed for the downcomer of PECS, the superstep design shows the highest mass flow rate and the lowest gas holdup in the downcomer as well as in the cooling channel. Compared with the existing design, the elimination of the horizontal part and the addition of an extra space above the vertical entrance to the downcomer seem to help the separation of the vapor

  8. A new approach to process control using Instability Index

    Science.gov (United States)

    Weintraub, Jeffrey; Warrick, Scott

    2016-03-01

    The merits of a robust Statistical Process Control (SPC) methodology have long been established. In response to the numerous SPC rule combinations, processes, and the high cost of containment, the Instability Index (ISTAB) is presented as a tool for managing these complexities. ISTAB focuses limited resources on key issues and provides a window into the stability of manufacturing operations. ISTAB takes advantage of the statistical nature of processes by comparing the observed average run length (OARL) to the expected run length (ARL), resulting in a gap value called the ISTAB index. The ISTAB index has three characteristic behaviors that are indicative of defects in an SPC instance. Case 1: The observed average run length is excessively long relative to expectation. ISTAB > 0 is indicating the possibility that the limits are too wide. Case 2: The observed average run length is consistent with expectation. ISTAB near zero is indicating that the process is stable. Case 3: The observed average run length is inordinately short relative to expectation. ISTAB system based on ISTAB as an enhancement to more traditional SPC approaches.

  9. Modal-based reduced-order model of BWR out-of phase instabilities

    International Nuclear Information System (INIS)

    Turso, J.A.; Edwards, R.M.; March-Leuba, J.

    1995-01-01

    For the past 40 yr, reduced-order modeling of boiling water reactor (BWR) dynamic behavior has been accomplished by several researchers. These models have been primarily concerned with providing insight into the so-called corewide neutron flux oscillation, where the power at each radial location in the core oscillates in unison. This is generally considered to be an illustration of the fundamental neutronic mode excited by the core thermal hydraulics. The time dependence of the fundamental mode is typically described by the point-kinetics equations, with one or more delayed-neutron groups. Thermal-hydraulic excitation of the first azimuthal harmonic mode, the so-called out-of-phase (OOP) instability, has been observed in operating BWRs. The temporal behavior of a low-order model of this phenomenon can be characterized using the modal point-kinetics formulation developed in this paper

  10. Simulation of local instabilities with the use of reduced order models

    International Nuclear Information System (INIS)

    Dykin, V.; Demaziere, C.; Lange, C.; Hennig, D.

    2011-01-01

    The development of an advanced reduced order model (ROM) with four heated channels, taking into account local, regional and core-wide oscillations, is described. The ROM contains three sub-models: a neutron-kinetic model (describing neutron transport), a thermal- hydraulic model (describing the coolant flow) and a heat transfer model (describing heat transfer between the fuel and the coolant). All these three models are coupled to each other, using two feedback mechanisms: void feedback and doppler feedback. Each of the sub-models is described by a set of reduced ordinary differential equations, derived from the corresponding time space-dependent partial differential equations by using different types of approximations and mathematical techniques. All three models were developed from past ROMs and, subsequently, were modified in order to fit the purpose of our investigations. One of the novelties of the present ROM is that it takes into account the effect of the first three neutronic modes, namely the fundamental, the first and the second azimuthal modes, as well as the effect of local oscillations on these modes. In order to have a proper representation of both azimuthal modes, a four heated channel ROM was developed. Another modification, compared to earlier work, is the determination of the coupling reactivity coefficients for both void fraction and fuel temperature, which were calculated explicitly by evaluating cross-section perturbations with the help of the SIMULATE-3 and the CORESIM codes. The ROM was thereafter applied to a channel instability event that occurred at the Swedish Forsmark-1 BWR in 1996/1997. The time signals for each of the modes were generated from the ROM and compared with the measurements, performed at the plant. Some qualitative comparison between the ROM and the measurements was made. The results could bear some significance in understanding the instability event and its coupling mechanism to core-wide oscillations. (author)

  11. Prediction of a Francis turbine prototype full load instability from investigations on the reduced scale model

    Science.gov (United States)

    Alligné, S.; Maruzewski, P.; Dinh, T.; Wang, B.; Fedorov, A.; Iosfin, J.; Avellan, F.

    2010-08-01

    The growing development of renewable energies combined with the process of privatization, lead to a change of economical energy market strategies. Instantaneous pricings of electricity as a function of demand or predictions, induces profitable peak productions which are mainly covered by hydroelectric power plants. Therefore, operators harness more hydroelectric facilities at full load operating conditions. However, the Francis Turbine features an axi-symmetric rope leaving the runner which may act under certain conditions as an internal energy source leading to instability. Undesired power and pressure fluctuations are induced which may limit the maximum available power output. BC Hydro experiences such constraints in a hydroelectric power plant consisting of four 435 MW Francis Turbine generating units, which is located in Canada's province of British Columbia. Under specific full load operating conditions, one unit experiences power and pressure fluctuations at 0.46 Hz. The aim of the paper is to present a methodology allowing prediction of this prototype's instability frequency from investigations on the reduced scale model. A new hydro acoustic vortex rope model has been developed in SIMSEN software, taking into account the energy dissipation due to the thermodynamic exchange between the gas and the surrounding liquid. A combination of measurements, CFD simulations and computation of eigenmodes of the reduced scale model installed on test rig, allows the accurate calibration of the vortex rope model parameters at the model scale. Then, transposition of parameters to the prototype according to similitude laws is applied and stability analysis of the power plant is performed. The eigenfrequency of 0.39 Hz related to the first eigenmode of the power plant is determined to be unstable. Predicted frequency of the full load power and pressure fluctuations at the unit unstable operating point is found to be in general agreement with the prototype measurements.

  12. Prediction of a Francis turbine prototype full load instability from investigations on the reduced scale model

    International Nuclear Information System (INIS)

    Alligne, S; Maruzewski, P; Avellan, F; Dinh, T; Wang, B; Fedorov, A; Iosfin, J

    2010-01-01

    The growing development of renewable energies combined with the process of privatization, lead to a change of economical energy market strategies. Instantaneous pricings of electricity as a function of demand or predictions, induces profitable peak productions which are mainly covered by hydroelectric power plants. Therefore, operators harness more hydroelectric facilities at full load operating conditions. However, the Francis Turbine features an axi-symmetric rope leaving the runner which may act under certain conditions as an internal energy source leading to instability. Undesired power and pressure fluctuations are induced which may limit the maximum available power output. BC Hydro experiences such constraints in a hydroelectric power plant consisting of four 435 MW Francis Turbine generating units, which is located in Canada's province of British Columbia. Under specific full load operating conditions, one unit experiences power and pressure fluctuations at 0.46 Hz. The aim of the paper is to present a methodology allowing prediction of this prototype's instability frequency from investigations on the reduced scale model. A new hydro acoustic vortex rope model has been developed in SIMSEN software, taking into account the energy dissipation due to the thermodynamic exchange between the gas and the surrounding liquid. A combination of measurements, CFD simulations and computation of eigenmodes of the reduced scale model installed on test rig, allows the accurate calibration of the vortex rope model parameters at the model scale. Then, transposition of parameters to the prototype according to similitude laws is applied and stability analysis of the power plant is performed. The eigenfrequency of 0.39 Hz related to the first eigenmode of the power plant is determined to be unstable. Predicted frequency of the full load power and pressure fluctuations at the unit unstable operating point is found to be in general agreement with the prototype measurements.

  13. Social instability stress in adolescent male rats reduces social interaction and social recognition performance and increases oxytocin receptor binding.

    Science.gov (United States)

    Hodges, Travis E; Baumbach, Jennet L; Marcolin, Marina L; Bredewold, Remco; Veenema, Alexa H; McCormick, Cheryl M

    2017-09-17

    Social experiences in adolescence are essential for displaying context-appropriate social behaviors in adulthood. We previously found that adult male rats that underwent social instability stress (SS) in adolescence had reduced social interactions with unfamiliar peers compared with non-stressed controls (CTL). Here we determined whether SS altered social recognition and social reward and brain oxytocin and vasopressin receptor density in adolescence. We confirmed that SS rats spent less time interacting with unfamiliar peers than did CTL rats (p=0.006). Furthermore, CTL rats showed a preference for novel over familiar conspecifics in a social recognition test whereas SS rats did not, which may reflect reduced recognition, impaired memory, or reduced preference for novelty in SS rats. The reward value of social interactions was not affected by SS based on conditioned place preference tests and based on the greater time SS rats spent investigating stimulus rats than did CTL rats when the stimulus rat was behind wire mesh (p=0.03). Finally, oxytocin receptor binding density was higher in the dorsal lateral septum and nucleus accumbens shell in SS rats compared with CTL rats (p=0.02, p=0.01, respectively). No effect of SS was found for vasopressin 1a receptor binding density in any of the brain regions analyzed. We discuss the extent to which the differences in social behavior exhibited after social instability in adolescence involve changes in social salience and social competency, and the possibility that changes in oxytocin signaling in the brain underlie the differences in social behavior. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  14. Effects of Noise and Time Delay Upon Active Control of Combustion Instabilities

    National Research Council Canada - National Science Library

    Zinn, Ben

    2001-01-01

    To improve the performance of practical active control system (ACS) for unstable combustors, the effects of system noise and ACS time delay upon combustion instabilities and the ACS performance were studied...

  15. Linear stability analysis of flow instabilities with a nodalized reduced order model in heated channel

    International Nuclear Information System (INIS)

    Paul, Subhanker; Singh, Suneet

    2015-01-01

    The prime objective of the presented work is to develop a Nodalized Reduced Order Model (NROM) to carry linear stability analysis of flow instabilities in a two-phase flow system. The model is developed by dividing the single phase and two-phase region of a uniformly heated channel into N number of nodes followed by time dependent spatial linear approximations for single phase enthalpy and two-phase quality between the consecutive nodes. Moving boundary scheme has been adopted in the model, where all the node boundaries vary with time due to the variation of boiling boundary inside the heated channel. Using a state space approach, the instability thresholds are delineated by stability maps plotted in parameter planes of phase change number (N pch ) and subcooling number (N sub ). The prime feature of the present model is that, though the model equations are simpler due to presence of linear-linear approximations for single phase enthalpy and two-phase quality, yet the results are in good agreement with the existing models (Karve [33]; Dokhane [34]) where the model equations run for several pages and experimental data (Solberg [41]). Unlike the existing ROMs, different two-phase friction factor multiplier correlations have been incorporated in the model. The applicability of various two-phase friction factor multipliers and their effects on stability behaviour have been depicted by carrying a comparative study. It is also observed that the Friedel model for friction factor calculations produces the most accurate results with respect to the available experimental data. (authors)

  16. An Effective Way to Control Numerical Instability of a Nonordinary State-Based Peridynamic Elastic Model

    Directory of Open Access Journals (Sweden)

    Xin Gu

    2017-01-01

    Full Text Available The constitutive modeling and numerical implementation of a nonordinary state-based peridynamic (NOSB-PD model corresponding to the classical elastic model are presented. Besides, the numerical instability problem of the NOSB-PD model is analyzed, and a penalty method involving the hourglass force is proposed to control the instabilities. Further, two benchmark problems, the static elastic deformation of a simple supported beam and the elastic wave propagation in a two-dimensional rod, are discussed with the present method. It proves that the penalty instability control method is effective in suppressing the displacement oscillations and improving the accuracy of calculated stress fields with a proper hourglass force coefficient, and the NOSB-PD approach with instability control can analyze the problems of structure deformation and elastic wave propagation well.

  17. Damping-controlled fluidelastic instability forces in multi-span tubes with loose supports

    International Nuclear Information System (INIS)

    Hassan, Marwan A.; Rogers, Robert J.; Gerber, Andrew G.

    2011-01-01

    This paper presents simulations of a loosely supported multi-span tube subjected to turbulence and fluidelastic instability forces in order to compare several time-domain fluid force models simulating the damping-controlled fluidelastic instability mechanism in tube arrays. These models include the negative damping model based on the Connors equation, fluid force coefficient-based models (Chen; Tanaka and Takahara), and two semi-analytical models (Price and Paidoussis; and Lever and Weaver). Time domain modelling challenges for each of these theories are discussed. The implemented models are validated against available experimental data. The linear simulations (without tube/support clearance) show that the Connors-equation based model exhibits the most conservative prediction of the critical flow velocity when the recommended design values for the Connors equation are used. The models are then utilized to simulate the nonlinear response of a three-span cantilever tube in a lattice bar support subjected to air crossflow. The tube is subjected to a single-phase flow passing over the spans where the flow velocity and the support clearance are varied. Special attention is paid to the tube/support interaction parameters that affect wear, such as impact forces, contact ratio, and normal work rate. As was seen for the linear cases, the reduced flow velocity at the instability threshold differs for the fluid force models considered. The investigated models do, however, exhibit similar response characteristics for the impact force, tip lift response, and work rate, except for the Connors-based model that overestimates the response and the tube/support interaction parameters for the loose support case, especially at large clearances.

  18. Suppression of resistive wall instabilities with distributed, independently controlled, active feedback coils

    International Nuclear Information System (INIS)

    Cates, C.; Shilov, M.; Mauel, M. E.; Navratil, G. A.; Maurer, D.; Mukherjee, S.; Nadle, D.; Bialek, J.; Boozer, A.

    2000-01-01

    External kink instabilities are suppressed in a tokamak experiment by either (1) energizing a distributed array of independently controlled active feedback coils mounted outside a segmented resistive wall or (2) inserting a second segmented wall having much higher electrical conductivity. When the active feedback coils are off and the highly conducting wall is withdrawn, kink instabilities excited by plasma current gradients grow at a rate comparable to the magnetic diffusion rate of the resistive wall. (c) 2000 American Institute of Physics

  19. Effect of fibular repositioning taping in adult basketball players with chronic ankle instability: a randomized, placebo-controlled, crossover trial.

    Science.gov (United States)

    Alves, Yanina; Ribeiro, Fernando; Silva, Anabela G

    2017-07-05

    Chronic ankle instability presents a high incidence and prevalence in basketbal players. It's important to develop strategies to reduce the functional and mechanical limitations resulting from this condition. To compare the effect of Mulligan ́s fibular repositioning taping with a placebo taping immediatly after application and after a running test (Yo-Yo IRT). 16 adult basketball players (10 male, 6 female) with chronic ankle instability and mean age 21.50 ± 2.76 years old. Assessment of static postural control (15 seconds of unipedal stance test with eyes closed in a force platform), functional performance (figure 8 hop test and lateral hop test) and neuromuscular control (peroneus longus latency time in sudden inversion) in two conditions: Mulligan and Placebo. No significant effect was found for the intervantion factor in both hop tests (p>0.170), but there was a significant effect for the time factor (p<0.03). For the peroneus longus latency time, there was a significant interaction between factors (p=0.028) and also for time (p=0.042). No significant effect was found for any of the static postural control variables (area, speed and total displacement) (p≥0.10). There was no differences between Mulligan's fibular repositioning taping and Placebo taping in postural control and functional performance in basketball players with chronic ankle instability. However, Mulligan's taping appears to reduce peroneus longus latency time after a running when compared with a placebo taping.

  20. Microsatellite instability is associated with reduced disease specific survival in stage III colon cancer.

    Science.gov (United States)

    Mohan, H M; Ryan, E; Balasubramanian, I; Kennelly, R; Geraghty, R; Sclafani, F; Fennelly, D; McDermott, R; Ryan, E J; O'Donoghue, D; Hyland, J M P; Martin, S T; O'Connell, P R; Gibbons, D; Winter, Des; Sheahan, K

    2016-11-01

    Up to 15% of colorectal cancers exhibit microsatellite instability (MSI), where errors in replication go unchecked due to defects in the mismatch repair system. This study aimed to determine survival in a large single-centre series of 1250 consecutive colorectal cancers subjected to universal MSI testing. Clinical and pathological features of patients with colorectal cancer identified on prospectively maintained colorectal and pathology databases at St. Vincent's University Hospital from 2004 to May 2012 were examined. Mismatch repair (MMR) status was determined by immunohistochemistry. Kaplan-Meier curves, the log-rank test and Cox regression were used to associate survival with clinical and pathological characteristics. Of the 1250 colorectal cancers in the study period, 11% exhibited MSI (n = 138). Patients with MSI tumours had significantly lower rates of lymph node and distant metastases (MSI N+ rate: 24.8% compared with MSS N+ rate: 46.2%, p colon cancer. However, patients with Stage III MSI colon cancers had a worse DSS than those with MSS tumours. Stage III MSI tumours exhibited higher rates of lymphovascular invasion and perineural invasion than Stage I/II MSI tumours. MSI is associated with a reduced risk of nodal and distant metastases, with an improved DSS in Stage I/II colon cancer. However, when MSI tumours progress to Stage III these patients had worse outcomes and pathological features. New strategies for this cohort of patients may be required to improve outcomes. Copyright © 2016. Published by Elsevier Ltd.

  1. Differences in kinematic control of ankle joint motions in people with chronic ankle instability.

    Science.gov (United States)

    Kipp, Kristof; Palmieri-Smith, Riann M

    2013-06-01

    People with chronic ankle instability display different ankle joint motions compared to healthy people. The purpose of this study was to investigate the strategies used to control ankle joint motions between a group of people with chronic ankle instability and a group of healthy, matched controls. Kinematic data were collected from 11 people with chronic ankle instability and 11 matched control subjects as they performed a single-leg land-and-cut maneuver. Three-dimensional ankle joint angles were calculated from 100 ms before, to 200 ms after landing. Kinematic control of the three rotational ankle joint degrees of freedom was investigated by simultaneously examining the three-dimensional co-variation of plantarflexion/dorsiflexion, toe-in/toe-out rotation, and inversion/eversion motions with principal component analysis. Group differences in the variance proportions of the first two principal components indicated that the angular co-variation between ankle joint motions was more linear in the control group, but more planar in the chronic ankle instability group. Frontal and transverse plane motions, in particular, contributed to the group differences in the linearity and planarity of angular co-variation. People with chronic ankle instability use a different kinematic control strategy to coordinate ankle joint motions during a single-leg landing task. Compared to the healthy group, the chronic ankle instability group's control strategy appeared to be more complex and involved joint-specific contributions that would tend to predispose this group to recurring episodes of instability. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Sensor-Based Optimized Control of the Full Load Instability in Large Hydraulic Turbines

    Directory of Open Access Journals (Sweden)

    Alexandre Presas

    2018-03-01

    Full Text Available Hydropower plants are of paramount importance for the integration of intermittent renewable energy sources in the power grid. In order to match the energy generated and consumed, Large hydraulic turbines have to work under off-design conditions, which may lead to dangerous unstable operating points involving the hydraulic, mechanical and electrical system. Under these conditions, the stability of the grid and the safety of the power plant itself can be compromised. For many Francis Turbines one of these critical points, that usually limits the maximum output power, is the full load instability. Therefore, these machines usually work far away from this unstable point, reducing the effective operating range of the unit. In order to extend the operating range of the machine, working closer to this point with a reasonable safety margin, it is of paramount importance to monitor and to control relevant parameters of the unit, which have to be obtained with an accurate sensor acquisition strategy. Within the framework of a large EU project, field tests in a large Francis Turbine located in Canada (rated power of 444 MW have been performed. Many different sensors were used to monitor several working parameters of the unit for all its operating range. Particularly for these tests, more than 80 signals, including ten type of different sensors and several operating signals that define the operating point of the unit, were simultaneously acquired. The present study, focuses on the optimization of the acquisition strategy, which includes type, number, location, acquisition frequency of the sensors and corresponding signal analysis to detect the full load instability and to prevent the unit from reaching this point. A systematic approach to determine this strategy has been followed. It has been found that some indicators obtained with different types of sensors are linearly correlated with the oscillating power. The optimized strategy has been determined

  3. Sensor-Based Optimized Control of the Full Load Instability in Large Hydraulic Turbines.

    Science.gov (United States)

    Presas, Alexandre; Valentin, David; Egusquiza, Mònica; Valero, Carme; Egusquiza, Eduard

    2018-03-30

    Hydropower plants are of paramount importance for the integration of intermittent renewable energy sources in the power grid. In order to match the energy generated and consumed, Large hydraulic turbines have to work under off-design conditions, which may lead to dangerous unstable operating points involving the hydraulic, mechanical and electrical system. Under these conditions, the stability of the grid and the safety of the power plant itself can be compromised. For many Francis Turbines one of these critical points, that usually limits the maximum output power, is the full load instability. Therefore, these machines usually work far away from this unstable point, reducing the effective operating range of the unit. In order to extend the operating range of the machine, working closer to this point with a reasonable safety margin, it is of paramount importance to monitor and to control relevant parameters of the unit, which have to be obtained with an accurate sensor acquisition strategy. Within the framework of a large EU project, field tests in a large Francis Turbine located in Canada (rated power of 444 MW) have been performed. Many different sensors were used to monitor several working parameters of the unit for all its operating range. Particularly for these tests, more than 80 signals, including ten type of different sensors and several operating signals that define the operating point of the unit, were simultaneously acquired. The present study, focuses on the optimization of the acquisition strategy, which includes type, number, location, acquisition frequency of the sensors and corresponding signal analysis to detect the full load instability and to prevent the unit from reaching this point. A systematic approach to determine this strategy has been followed. It has been found that some indicators obtained with different types of sensors are linearly correlated with the oscillating power. The optimized strategy has been determined based on the

  4. On mill flow rate and fineness control in cement grinding circuits: instability and delayed measurements

    International Nuclear Information System (INIS)

    Lepore, R.; Boulvin, M.; Renotte, C.; Remy, M.

    1999-01-01

    A control structure for the mill flow rate and the product fineness is designed, with the feed flow rate and the classifier characteristic as the manipulated variables. Experimental results from a plant highlight the instability of the grinding circuit. A model previously developed by the authors stresses the major influence of the classifier nonlinearities onto this instability. A cascade control structure has been designed and implemented on site. The measurements of the product fineness, sensitive to material grindability fluctuations, are randomly time-delayed. The control structure uses a fineness estimator based on an adaptive scheme and a time delay compensator. (author)

  5. The significance of microsatellite instability in colorectal cancer after controlling for clinicopathological factors.

    Science.gov (United States)

    Kang, Sanghee; Na, Younghyun; Joung, Sung Yup; Lee, Sun Il; Oh, Sang Cheul; Min, Byung Wook

    2018-03-01

    The colorectal cancer (CRC) patients with microsatellite instability (MSI) have distinct clinicopathological characteristics consisting of factors predicting positive and negative outcomes, such as a high lymph node harvest and poor differentiation. In this study, we measured the value of MSI as a prognostic factor after controlling for these discrepant factors. A total of 603 patients who underwent curative surgery for stages I to III colorectal cancer were enrolled. The patients were divided into microsatellite instability high (MSI-H) and microsatellite stable/microsatellite instability low (MSS/MSI-L) groups. Propensity score matching was used to match clinicopathological factors between the 2 groups. MSI-H patients had a high lymph node harvest (median: 31.0 vs 23.0, P controlling for pathological characteristics, MSI-H could be a potent prognostic factor regarding patient survival.

  6. Movement Strategies among Groups of Chronic Ankle Instability, Coper, and Control.

    Science.gov (United States)

    Son, S Jun; Kim, Hyunsoo; Seeley, Matthew K; Hopkins, J Ty

    2017-08-01

    Comprehensive evaluation of movement strategies during functional movement is a difficult undertaking. Because of this challenge, studied movements have been oversimplified. Furthermore, evaluating movement strategies at only a discrete time point(s) provide limited insight into how movement strategies may change or adapt in chronic ankle instability (CAI) patients. This study aimed to identify abnormal movement strategies in individuals with a history of ankle sprain injury during a sports maneuver compared with healthy controls. Sixty-six participants, consisting of 22 CAI patients, 22 ankle sprain copers, and 22 healthy controls, participated in this study. Functional profiles of lower extremity kinematics, kinetics, and EMG activation from initial contact (0% of stance) to toe-off (100% of stance) were collected and analyzed during a jump landing/cutting task using a functional data analysis approach. Compared with copers, CAI patients displayed landing positions of less plantarflexion, less inversion, more knee flexion, more hip flexion, and less hip abduction during the first 25% of stance. However, restricted dorsiflexion angle was observed in both CAI patients and copers relative to controls during the midlanding to mid-side-cutting phase when the ankle and knee reached its peak range of motion (e.g., dorsiflexion and knee flexion). Reduced EMG activation of tibialis anterior, peroneus longus, medial gastrocnemius, and gluteus medius may be due to altered kinematics that reduce muscular demands on the involved muscles. CAI patients displayed altered movement strategies, perhaps in an attempt to avoid perceived positions of risk. Although sagittal joint positions seemed to increase the external torque on the knee and hip extensors, frontal joint positions appeared to reduce the muscular demands on evertor and hip abductor muscles.

  7. [Damage control in trauma patients with hemodynamic instability].

    Science.gov (United States)

    Müller, Thorben; Doll, Dietrich; Kliebe, Frank; Ruchholtz, Steffen; Kühne, Christian

    2010-10-01

    The term "Damage-control" is borrowed from naval terminology. It means the initial control of a damaged ship. Because of the lethal triad in multiple injured patients the classical concept of definitive surgically therapy in the acute phase of the injury has a high rate of complications such as exsanguination, sepsis, heart failure and multiple organ failure. The core idea of the damage control concept was to minimize the additional trauma by surgical operations in these critical patients in the first phase. This means temporary control of a hemorrhage and measures for stopping abdominal contamination. After 24 - 48 hours in the intensive care unit and correction of physiological disturbances further interventions are performed for definitively treatment of the injuries. Summarized, the damage control strategy comprises an abbreviated operation, intensive care unit resuscitation, and a return to the operating room for the definitive operation after hemodynamic stabilisation of the patient. © Georg Thieme Verlag Stuttgart · New York.

  8. Investigation of MHD instabilities and control in KSTAR preparing for high beta operation

    Science.gov (United States)

    Park, Y. S.; Sabbagh, S. A.; Bialek, J. M.; Berkery, J. W.; Lee, S. G.; Ko, W. H.; Bak, J. G.; Jeon, Y. M.; Park, J. K.; Kim, J.; Hahn, S. H.; Ahn, J.-W.; Yoon, S. W.; Lee, K. D.; Choi, M. J.; Yun, G. S.; Park, H. K.; You, K.-I.; Bae, Y. S.; Oh, Y. K.; Kim, W.-C.; Kwak, J. G.

    2013-08-01

    Initial H-mode operation of the Korea Superconducting Tokamak Advanced Research (KSTAR) is expanded to higher normalized beta and lower plasma internal inductance moving towards design target operation. As a key supporting device for ITER, an important goal for KSTAR is to produce physics understanding of MHD instabilities at long pulse with steady-state profiles, at high normalized beta, and over a wide range of plasma rotation profiles. An advance from initial plasma operation is a significant increase in plasma stored energy and normalized beta, with Wtot = 340 kJ, βN = 1.9, which is 75% of the level required to reach the computed ideal n = 1 no-wall stability limit. The internal inductance was lowered to 0.9 at sustained H-mode duration up to 5 s. In ohmically heated plasmas, the plasma current reached 1 MA with prolonged pulse length up to 12 s. Rotating MHD modes are observed in the device with perturbations having tearing rather than ideal parity. Modes with m/n = 3/2 are triggered during the H-mode phase but are relatively weak and do not substantially reduce Wtot. In contrast, 2/1 modes to date only appear when the plasma rotation profiles are lowered after H-L back-transition. Subsequent 2/1 mode locking creates a repetitive collapse of βN by more than 50%. Onset behaviour suggests the 3/2 mode is close to being neoclassically unstable. A correlation between the 2/1 mode amplitude and local rotation shear from an x-ray imaging crystal spectrometer suggests that the rotation shear at the mode rational surface is stabilizing. As a method to access the ITER-relevant low plasma rotation regime, plasma rotation alteration by n = 1, 2 applied fields and associated neoclassical toroidal viscosity (NTV) induced torque is presently investigated. The net rotation profile change measured by a charge exchange recombination diagnostic with proper compensation of plasma boundary movement shows initial evidence of non-resonant rotation damping by the n = 1, 2 applied

  9. Investigation of MHD instabilities and control in KSTAR preparing for high beta operation

    International Nuclear Information System (INIS)

    Park, Y.S.; Sabbagh, S.A.; Bialek, J.M.; Berkery, J.W.; Lee, S.G.; Ko, W.H.; Bak, J.G.; Jeon, Y.M.; Kim, J.; Hahn, S.H.; Yoon, S.W.; Lee, K.D.; You, K.-I.; Bae, Y.S.; Oh, Y.K.; Park, J.K.; Ahn, J.-W.; Choi, M.J.; Yun, G.S.; Park, H.K.

    2013-01-01

    Initial H-mode operation of the Korea Superconducting Tokamak Advanced Research (KSTAR) is expanded to higher normalized beta and lower plasma internal inductance moving towards design target operation. As a key supporting device for ITER, an important goal for KSTAR is to produce physics understanding of MHD instabilities at long pulse with steady-state profiles, at high normalized beta, and over a wide range of plasma rotation profiles. An advance from initial plasma operation is a significant increase in plasma stored energy and normalized beta, with W tot = 340 kJ, β N = 1.9, which is 75% of the level required to reach the computed ideal n = 1 no-wall stability limit. The internal inductance was lowered to 0.9 at sustained H-mode duration up to 5 s. In ohmically heated plasmas, the plasma current reached 1 MA with prolonged pulse length up to 12 s. Rotating MHD modes are observed in the device with perturbations having tearing rather than ideal parity. Modes with m/n = 3/2 are triggered during the H-mode phase but are relatively weak and do not substantially reduce W tot . In contrast, 2/1 modes to date only appear when the plasma rotation profiles are lowered after H–L back-transition. Subsequent 2/1 mode locking creates a repetitive collapse of β N by more than 50%. Onset behaviour suggests the 3/2 mode is close to being neoclassically unstable. A correlation between the 2/1 mode amplitude and local rotation shear from an x-ray imaging crystal spectrometer suggests that the rotation shear at the mode rational surface is stabilizing. As a method to access the ITER-relevant low plasma rotation regime, plasma rotation alteration by n = 1, 2 applied fields and associated neoclassical toroidal viscosity (NTV) induced torque is presently investigated. The net rotation profile change measured by a charge exchange recombination diagnostic with proper compensation of plasma boundary movement shows initial evidence of non-resonant rotation damping by the n = 1, 2

  10. Feedback control of thermal instability by compression and decompression

    International Nuclear Information System (INIS)

    Okamoto, M.; Hirano, K.; Amano, T.; Ohnishi, M.

    1983-01-01

    Active feedback control of the fusion output power by means of plasma compression-decompression is considered with the purpose of achieving steady-state plasma ignition in a tokamak. A simple but realistic feedback control system is modelled and zero-dimensional energy balance equations are solved numerically by taking into account the errors in the measurements, a procedure that is necessary for the feedback control. It is shown that the control can stabilize the thermal runaway completely and maintain steady-state operation without any significant change in major radius or thermal output power. Linear stability is analysed for a general type of scaling law, and the dependence of the stability conditions on the scaling law is studied. The possibility of load-following operation is considered. Finally, a one-dimensional analysis is applied to the large-aspect-ratio case. (author)

  11. Detection and control of combustion instability based on the concept of dynamical system theory

    Science.gov (United States)

    Gotoda, Hiroshi; Shinoda, Yuta; Kobayashi, Masaki; Okuno, Yuta; Tachibana, Shigeru

    2014-02-01

    We propose an online method of detecting combustion instability based on the concept of dynamical system theory, including the characterization of the dynamic behavior of combustion instability. As an important case study relevant to combustion instability encountered in fundamental and practical combustion systems, we deal with the combustion dynamics close to lean blowout (LBO) in a premixed gas-turbine model combustor. The relatively regular pressure fluctuations generated by thermoacoustic oscillations transit to low-dimensional intermittent chaos owing to the intermittent appearance of burst with decreasing equivalence ratio. The translation error, which is characterized by quantifying the degree of parallelism of trajectories in the phase space, can be used as a control variable to prevent LBO.

  12. Detection and control of combustion instability based on the concept of dynamical system theory.

    Science.gov (United States)

    Gotoda, Hiroshi; Shinoda, Yuta; Kobayashi, Masaki; Okuno, Yuta; Tachibana, Shigeru

    2014-02-01

    We propose an online method of detecting combustion instability based on the concept of dynamical system theory, including the characterization of the dynamic behavior of combustion instability. As an important case study relevant to combustion instability encountered in fundamental and practical combustion systems, we deal with the combustion dynamics close to lean blowout (LBO) in a premixed gas-turbine model combustor. The relatively regular pressure fluctuations generated by thermoacoustic oscillations transit to low-dimensional intermittent chaos owing to the intermittent appearance of burst with decreasing equivalence ratio. The translation error, which is characterized by quantifying the degree of parallelism of trajectories in the phase space, can be used as a control variable to prevent LBO.

  13. A reactive decision-making approach to reduce instability in a Master Production Schedule

    OpenAIRE

    Herrera , Carlos; Belmokhtar Berraf , Sana; Thomas , André; Parada , Victor

    2016-01-01

    International audience; One of the primary factors that impact the master production scheduling performance is demand fluctuation, which leads to frequently updated decisions, thereby causing instability. Consequently, global cost deteriorates, and productivity decreases. A reactive approach based on parametric mixed-integer programming is proposed that aims to provide a set of plans such that a compromise between production cost and production stability is ensured. Several stability measures...

  14. Reducing work disability in Ankylosing Spondylitis – development of a work instability scale for AS

    Directory of Open Access Journals (Sweden)

    Helliwell Philip

    2009-06-01

    Full Text Available Abstract Background The Work Instability Scale for Rheumatoid Arthritis (RA-WIS is established and is used by physicians to identify patients at risk of job loss for rapid intervention. The study objective was to explore the concept of Work Instability (a mismatch between an individual's abilities and job demands in Ankylosing Spondylitis (AS and develop a Work Instability Scale specific to this population. Methods New items generated from qualitative interviews were combined with items from the RA-WIS to form a draft AS-WIS. Rasch analysis was used to examine the scaling properties of the AS-WIS using data generated through a postal survey. The scale was validated against a gold standard of expert assessment, a test-retest survey examined reliability. Results Fifty-seven participants who were in work returned the postal survey. Of the original 55 items 38 were shown to fit the Rasch model (χ2 37.5; df 38; p 0.494 and free of bias for gender and disease duration. Following analysis for discrimination against the gold standard assessments 20 items remained with good fit to the model (χ2 24.8; df 20; p 0.21. Test-retest reliability was 0.94. Conclusion The AS-WIS is a self-administered scale which meets the stringent requirements of modern measurement. Used as a screening tool it can identify those experiencing a mismatch at work who are at risk of job retention problems and work disability. Work instability is emerging as an important indication for the use of biologics, thus the AS-WIS has the potential to become an important outcome measure.

  15. Architectures and Algorithms for Control and Diagnostics of Coupled-Bunch Instabilities in Circular Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Teytelman, Dmitry

    2003-07-08

    Modern light sources and circular colliders employ large numbers of high-intensity particle bunches in order to achieve high luminosity. The electromagnetic coupling of bunches via resonant structures causes coherent instabilities at high beam currents. Achieving high luminosity requires the control of such unstable motion. Feedback control is challenging due to wideband nature of the problem with up to 250 MHz bandwidths required. This thesis presents digital signal processing architectures and diagnostic techniques for control of longitudinal and transverse coupled-bunch instabilities. Diagnostic capabilities integrated into the feedback system allow one to perform fast transient measurements of unstable dynamics by perturbing the beam from the controlled state via feedback and recording the time-domain response. Such measurements enable one to thoroughly characterize plant (beam) dynamics as well as performance of the feedback system. Beam dynamics can change significantly over the operating range of accelerator currents and energies . Here we present several methods for design of robust stabilizing feedback controllers. Experimental results from several accelerators are presented. A new baseband architecture for transverse feedback is described that compactly implements the digital processing functions using field-programmable gate array devices. The architecture is designed to be software configurable so that the same hardware can be used for instability control in different accelerators.

  16. Architectures and Algorithms for Control and Diagnostics of Coupled-Bunch Instabilities in Circular Accelerators

    International Nuclear Information System (INIS)

    Teytelman, Dmitry

    2003-01-01

    Modern light sources and circular colliders employ large numbers of high-intensity particle bunches in order to achieve high luminosity. The electromagnetic coupling of bunches via resonant structures causes coherent instabilities at high beam currents. Achieving high luminosity requires the control of such unstable motion. Feedback control is challenging due to wideband nature of the problem with up to 250 MHz bandwidths required. This thesis presents digital signal processing architectures and diagnostic techniques for control of longitudinal and transverse coupled-bunch instabilities. Diagnostic capabilities integrated into the feedback system allow one to perform fast transient measurements of unstable dynamics by perturbing the beam from the controlled state via feedback and recording the time-domain response. Such measurements enable one to thoroughly characterize plant (beam) dynamics as well as performance of the feedback system. Beam dynamics can change significantly over the operating range of accelerator currents and energies . Here we present several methods for design of robust stabilizing feedback controllers. Experimental results from several accelerators are presented. A new baseband architecture for transverse feedback is described that compactly implements the digital processing functions using field-programmable gate array devices. The architecture is designed to be software configurable so that the same hardware can be used for instability control in different accelerators

  17. Nonlinear instabilities induced by the F coil power amplifier at FTU: Modeling and control

    International Nuclear Information System (INIS)

    Zaccarian, L.; Boncagni, L.; Cascone, D.; Centioli, C.; Cerino, S.; Gravanti, F.; Iannone, F.; Mecocci, F.; Pangione, L.; Podda, S.; Vitale, V.; Vitelli, R.

    2009-01-01

    In this paper we focus on the instabilities caused by the nonlinear behavior of the F coil current amplifier at FTU. This behavior induces closed-loop instability of the horizontal position stabilizing loop whenever the requested current is below the circulating current level. In the paper we first illustrate a modeling phase where nonlinear dynamics are derived and identified to reproduce the open-loop responses measured by the F coil current amplifier. The derived model is shown to successfully reproduce the experimental behavior by direct comparison with experimental data. Based on this dynamic model, we then reproduce the closed-loop scenario of the experiment and show that the proposed nonlinear model successfully reproduces the nonlinear instabilities experienced in the experimental sessions. Given the simulation setup, we next propose a nonlinear control solution to this instability problem. The proposed solution is shown to recover stability in closed-loop simulations. Experimental tests are scheduled for the next experimental campaign after the FTU restart.

  18. On the morphological instability of a bubble during inertia-controlled growth

    Science.gov (United States)

    Martyushev, L. M.; Birzina, A. I.; Soboleva, A. S.

    2018-06-01

    The morphological stability of a spherical bubble growing under inertia control is analyzed. Based on the comparison of entropy productions for a distorted and undistorted surface and using the maximum entropy production principle, the morphological instability of the bubble under arbitrary amplitude distortions is shown. This result allows explaining a number of experiments where the surface roughness of bubbles was observed during their explosive-type growth.

  19. Dynamic ankle control in athletes with ankle instability during sports maneuvers.

    Science.gov (United States)

    Lin, Cheng-Feng; Chen, Chin-Yang; Lin, Chia-Wei

    2011-09-01

    Ankle sprain is a common sports injury. While the effects of static constraints in stabilizing the ankle joint are relatively well understood, those of dynamic constraints are less clear and require further investigation. This study was undertaken to evaluate the dynamic stability of the ankle joint during the landing phase of running and stop-jump maneuvers in athletes with and without chronic ankle instability (CAI). Controlled laboratory study. Fifteen athletes with CAI and 15 age-matched athletes without CAI performed running and stop-jump landing tasks. The dynamic ankle joint stiffness, tibialis anterior (TA)/peroneus longus (PL) and TA/gastrocnemius lateralis (GL) co-contraction indices, ankle joint angle, and root-mean-square (RMS) of the TA, PL, and GL electromyographic signals were measured during each task. During running, the CAI group exhibited a greater ankle inversion angle than the control group in the pre-landing phase (P = .012-.042) and a lower dynamic ankle joint stiffness in the post-landing phase (CAI: 0.109 ± 0.039 N·m/deg; control: 0.150 ± 0.068 N·m/deg; P = .048). In the stop-jump landing task, athletes with CAI had a significantly lower TA/PL co-contraction index during the pre-landing phase (CAI: 49.1 ± 19; control: 64.8 ± 16; P = .009). In addition, the CAI group exhibited a greater ankle inversion (P = .049), a lower peak eversion (P = .04), and a smaller RMS of the PL electromyographic signal in the post-landing phase (CAI: 0.73 ± 0.32; control: 0.51 ± 0.22; P = .04). Athletes with CAI had a relatively inverted ankle, reduced muscle co-contraction, and a lower dynamic stiffness in the ankle joint during the landing phase of sports maneuvers and this may jeopardize the stability of the ankle. Sports training or rehabilitation programs should differentiate between the pre-landing and post-landing phases of sports maneuvers, and should educate athletes to land with an appropriate ankle position and muscle recruitment.

  20. One-dimensional flame instability and control of burning in fire-chamber

    Directory of Open Access Journals (Sweden)

    Victor E. Volkov

    2015-03-01

    Full Text Available The flame stability with regard to one-dimensional exponential perturbations both for the combustion in the fire-chamber and the flame propagating in closed tubes or chambers is investigated. It is proved that both stability and instability are possible for the combustion process. At the same time the one-dimensional flame instability is guaranteed near the front wall of the fire-chamber where the fuel supply is realized. Therefore the control of combustion in the fire-chamber leads to support of the flame at the maximum possible distance from the front wall of the fire-chamber to prevent the vibratory combustion or to diminish intensity of pulsations if these pulsations are inevitable.

  1. A real-time data acquisition and elaboration system for instabilities control in the FTU tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Alessi, E., E-mail: alessi@ifp.cnr.it [Associazione EURATOM-ENEA, IFP-CNR, Milano (Italy); Boncagni, L. [Associazione EURATOM-ENEA, C.R. Frascati (Italy); Galperti, C.; Marchetto, C.; Nowak, S.; Sozzi, C. [Associazione EURATOM-ENEA, IFP-CNR, Milano (Italy); Apruzzese, G. [Associazione EURATOM-ENEA, C.R. Frascati (Italy); Bin, W. [Associazione EURATOM-ENEA, IFP-CNR, Milano (Italy); Belli, F.; Botrugno, A. [Associazione EURATOM-ENEA, C.R. Frascati (Italy); Bruschi, A.; Cirant, S. [Associazione EURATOM-ENEA, IFP-CNR, Milano (Italy); D' Antona, G.; Davoudi, M. [Politecnico di Milano, Dipartimento di Elettrotecnica (Italy); Figini, L. [Associazione EURATOM-ENEA, IFP-CNR, Milano (Italy); Ferrero, R. [Politecnico di Milano, Dipartimento di Elettrotecnica (Italy); Gabellieri, L. [Associazione EURATOM-ENEA, C.R. Frascati (Italy); Garavaglia, S.; Granucci, G. [Associazione EURATOM-ENEA, IFP-CNR, Milano (Italy); Grosso, A. [Associazione EURATOM-ENEA, C.R. Frascati (Italy); and others

    2013-08-21

    A real-time data acquisition and elaboration system is being implemented to control the new ECH launcher recently installed at FTU (Frascati Tokamak Upgrade). The system is aimed at controlling different kinds of magnetohydrodynamic instabilities, in particular the deleterious 3/2 and 2/1 (neoclassical) tearing modes, (N)TM, and the saw teeth period in order to prevent the seeding of NTMs. The complete system is presented here together with preliminary offline and real-time tests. © 2001 Elsevier Science. All rights reserved.

  2. Difference in postural control between patients with functional and mechanical ankle instability.

    Science.gov (United States)

    Chen, Henry; Li, Hong-Yun; Zhang, Jian; Hua, Ying-Hui; Chen, Shi-Yi

    2014-10-01

    Lateral ankle sprain is one of the most common injuries. Since the structural and pathological differences in mechanical ankle instability (MAI) and functional ankle instability (FAI) may not be the same, it may be better to treat these as separate groups. The purpose of this study was to compare the difference in postural sway between MAI and FAI in patients with chronic ankle instability (CAI). Twenty-six patients with CAI and 14 healthy control participants were included in the study. The CAI patients were subdivided into MAI (15 patients) and FAI (11 patients) groups. Patients who were diagnosed with lateral ankle ligaments rupture by magnetic resonance imaging and ultrasonography were assigned to the MAI group. All participants performed single-limb postural sway tests 3 times on each leg with eyes closed and open. The average distances from the mean center of pressure position in the mediolateral and anteroposterior directions were recorded and compared among the 3 groups. The unstable ankles in the MAI group showed significantly greater postural sway in the anterior, posterior, and medial directions compared with those in the control group with eyes closed. With eyes open, significantly greater postural sway was found in the anterior direction. In the FAI group, no difference was found in postural sway compared with those in the control group. The MAI group showed significantly greater postural sway in the anterior direction compared with the FAI group with eyes closed and open. No significant difference in postural sway was found between the unstable and stable ankles in the MAI or FAI groups, with or without vision. Patients with MAI have deficits in postural control, especially in anterior-posterior directions. However, no difference was found in postural sway in patients with FAI compared with healthy people. As MAI patients suffer from deficits in postural control, balance training should be applied in those patients. In addition, special training

  3. Mind the gap: a flow instability controlled by particle-surface distance

    Science.gov (United States)

    Driscoll, Michelle; Delmotte, Blaise; Youssef, Mena; Sacanna, Stefano; Donev, Aleksandar; Chaikin, Paul

    2016-11-01

    Does a rotating particle always spin in place? Not if that particle is near a surface: rolling leads to translational motion, as well as very strong flows around the particle, even quite far away. These large advective flows strongly couple the motion of neighboring particles, giving rise to strong collective effects in groups of rolling particles. Using a model experimental system, weakly magnetic colloids driven by a rotating magnetic field, we observe that driving a compact group of microrollers leads to a new kind of flow instability. First, an initially uniformly-distributed strip of particles evolves into a shock structure, and then it becomes unstable, emitting fingers with a well-defined wavelength. Using 3D large-scale simulations in tandem with our experiments, we find that the instability wavelength is controlled not by the driving torque or the fluid viscosity, but a geometric parameter: the microroller's distance above the container floor. Furthermore, we find that the instability dynamics can be reproduced using only one ingredient: hydrodynamic interactions near a no-slip boundary.

  4. Multi-resolution Delta-plus-SPH with tensile instability control: Towards high Reynolds number flows

    Science.gov (United States)

    Sun, P. N.; Colagrossi, A.; Marrone, S.; Antuono, M.; Zhang, A. M.

    2018-03-01

    It is well known that the use of SPH models in simulating flow at high Reynolds numbers is limited because of the tensile instability inception in the fluid region characterized by high vorticity and negative pressure. In order to overcome this issue, the δ+-SPH scheme is modified by implementing a Tensile Instability Control (TIC). The latter consists of switching the momentum equation to a non-conservative formulation in the unstable flow regions. The loss of conservation properties is shown to induce small errors, provided that the particle distribution is regular. The latter condition can be ensured thanks to the implementation of a Particle Shifting Technique (PST). The novel variant of the δ+-SPH is proved to be effective in preventing the onset of tensile instability. Several challenging benchmark tests involving flows past bodies at large Reynolds numbers have been used. Within this a simulation characterized by a deforming foil that resembles a fish-like swimming body is used as a practical application of the δ+-SPH model in biological fluid mechanics.

  5. Specificity of Affective Instability in Patients With Borderline Personality Disorder Compared to Posttraumatic Stress Disorder, Bulimia Nervosa, and Healthy Controls

    Science.gov (United States)

    Santangelo, Philip; Mussgay, Lutz; Sawitzki, Günther; Trull, Timothy J.; Reinhard, Iris; Steil, Regina; Klein, Christoph; Bohus, Martin; Ebner-Priemer, Ulrich W.

    2014-01-01

    Affective instability is a core feature of borderline personality disorder (BPD). The use of advanced assessment methodologies and appropriate statistical analyses has led to consistent findings that indicate a heightened instability in patients with BPD compared with healthy controls. However, few studies have investigated the specificity of affective instability among patients with BPD with regard to relevant clinical control groups. In this study, 43 patients with BPD, 28 patients with posttraumatic stress disorder (PTSD), 20 patients with bulimia nervosa (BN), and 28 healthy controls carried e-diaries for 24 hours and were prompted to rate their momentary affective states approximately every 15 minutes while awake. To quantify instability, we used 3 state-of-the-art indices: multilevel models for squared successive differences (SSDs), multilevel models for probability of acute changes (PACs), and aggregated point-by-point changes (APPCs). Patients with BPD displayed heightened affective instability for emotional valence and distress compared with healthy controls, regardless of the specific instability indices. These results directly replicate earlier studies. However, affective instability did not seem to be specific to patients with BPD. With regard to SSDs, PACs, and APPCs, patients with PTSD or BN showed a similar heightened instability of affect (emotional valence and distress) to that of patients with BPD. Our results give raise to the discussion if affective instability is a transdiagnostic or a disorder-specific mechanism. Current evidence cannot answer this question, but investigating psychopathological mechanisms in everyday life across disorders is a promising approach to enhance validity and specificity of mental health diagnoses. PMID:24661176

  6. Reduced order models inertial manifold and global bifurcations: searching instability boundaries in nuclear power systems

    International Nuclear Information System (INIS)

    Suarez Antola, R.

    2009-01-01

    In the framework of an analytic or numerical model of a BWR power plant, this could imply first to find an suitable approximation to the solution manifold of the differential equations describing the stability behaviour of this nonlinear system, and then a classification of the different solution types concerning their relation with the operational safety of the power plant, by distributing the different solution types in relation with the exclusion region of the power-flow map. Then the goal is to obtain the best attainable qualitative and quantitative global picture of plant dynamics. To do this, the construction and the analysis of the so called reduced order models (Rom) seems a necessary step. A reduced order model results after the full system of coupled nonlinear partial differential equations of the plant is reduced to a system of coupled nonlinear ordinary differential equations

  7. Instability of supercritical porosity in highly doped ceria under reduced oxygen partial pressure

    DEFF Research Database (Denmark)

    Teocoli, Francesca; Ni, De Wei; Esposito, Vincenzo

    2015-01-01

    The thermomechanical behavior and microstructural evolution of low relative density (∼0.40) gadolinium-doped ceria are characterized under oxidative and reducing conditions at high temperatures. The electronic defects generated in the structure by Ce4+ to Ce3+ reduction play an important role on ...

  8. Control of secondary instability of the crossflow and Görtler-like vortices (Success and problems)

    Science.gov (United States)

    Kozlov, Viktor V.; Grek, Genrich R.

    The secondary instability on a group of crossflow vortices developing in a swept wing boundary layer is described. It is shown that, for travelling waves, there is a region of linear development, and the growth rate of disturbances appreciably depends on the separation between the vortices. Methods of controlling the secondary instability of the vortices by a controlled wave and local suction are proposed and substantiated. The stability of a flat plate boundary layer modulated by G&ou ml;rtler-like stationary vortices is described. Vortices were generated inside the boundary layer by means of roughness elements arranged in a regular array along the spanwise (z) direction. Transition is not caused directly by these structures, but by the growth of small amplitude travelling waves riding on top of the steady vortices. This situation is analogous to the transition process in Görtler and cross-flows. The waves were found to amplify up to a stage where higher harmonics are gener ated, leading to turbulent breakdown and disintegration of the spanwise boundary layer structure. For strong modulations, the observed instability is quite powerful, and can be excited "naturally" by small uncontrollable background disturbances. Controlled oscillations were then introduced by means of a vibrating ribbon, allowing a detailed investigation of the wave characteristics. The instability seems to be associated with the spanwise gradients of the mean flow, , and at all z-positions, the maximum wave amplitude was found at a wall-normal position where the mean velocity is equal to the phase velocity of the wave, U(y)=c, i.e., at the local critical layer. Unstable waves were observed at frequency well above those for which Tollmien-Schlichting (TS) waves amplify in the Blasius boundary layer. Excitation at lower frequencies and milder basic flow modulation showed that TS-type waves may a lso develop. Study of the transition control in that flow by means of riblets shows that the effect

  9. Architecture and technology of 500 Msample/s feedback systems for control of coupled-bunch instabilities

    International Nuclear Information System (INIS)

    Teytelman, Dmitry

    2000-01-01

    Feedback control of coupled-bunch instabilities presents many challenges. Control bandwidths up to 250 MHz are required to damp all of the unstable coupled-bunch modes in recent accelerators. A digital parallel-processing array with 80 DSPs has been developed to control longitudinal instabilities in PEP-II/ALS/DA NE machines. Here the authors present a description of the architecture as well as the technologies used to implement 500 Msample/s real-time control system with 2,000 FIR filtering channels. Algorithms for feedback control, data acquisition, and analysis are described and measurements from ALS are presented

  10. Instability of a two-step Rankine vortex in a reduced gravity QG model

    Energy Technology Data Exchange (ETDEWEB)

    Perrot, Xavier [Laboratoire de Météorologie Dynamique, Ecole Normale Supérieure, 24 rue Lhomond, F-75005 Paris (France); Carton, Xavier, E-mail: xperrot@lmd.ens.fr, E-mail: xcarton@univ-brest.fr [Laboratoire de Physique des Océans, Université de Bretagne Occidentale, 6 avenue Le Gorgeu, F-29200 Brest (France)

    2014-06-01

    We investigate the stability of a steplike Rankine vortex in a one-active-layer, reduced gravity, quasi-geostrophic model. After calculating the linear stability with a normal mode analysis, the singular modes are determined as a function of the vortex shape to investigate short-time stability. Finally we determine the position of the critical layer and show its influence when it lies inside the vortex. (papers)

  11. Reduced order models, inertial manifolds, and global bifurcations: searching instability boundaries in nuclear power systems

    Energy Technology Data Exchange (ETDEWEB)

    Suarez-Antola, Roberto, E-mail: roberto.suarez@miem.gub.u, E-mail: rsuarez@ucu.edu.u [Universidad Catolica del Uruguay, Montevideo (Uruguay). Fac. de Ingenieria y Tecnologias. Dept. de Matematica; Ministerio de Industria, Energia y Mineria, Montevideo (Uruguay). Direccion General de Secretaria

    2011-07-01

    One of the goals of nuclear power systems design and operation is to restrict the possible states of certain critical subsystems to remain inside a certain bounded set of admissible states and state variations. In the framework of an analytic or numerical modeling process of a BWR power plant, this could imply first to find a suitable approximation to the solution manifold of the differential equations describing the stability behavior, and then a classification of the different solution types concerning their relation with the operational safety of the power plant. Inertial manifold theory gives a foundation for the construction and use of reduced order models (ROM's) of reactor dynamics to discover and characterize meaningful bifurcations that may pass unnoticed during digital simulations done with full scale computer codes of the nuclear power plant. The March-Leuba's BWR ROM is generalized and used to exemplify the analytical approach developed here. A nonlinear integral-differential equation in the logarithmic power is derived. Introducing a KBM Ansatz, a coupled set of two nonlinear ordinary differential equations is obtained. Analytical formulae are derived for the frequency of oscillation and the parameters that determine the stability of the steady states, including sub- and supercritical PAH bifurcations. A Bautin's bifurcation scenario seems possible on the power-flow plane: near the boundary of stability, a region where stable steady states are surrounded by unstable limit cycles surrounded at their turn by stable limit cycles. The analytical results are compared with recent digital simulations and applications of semi-analytical bifurcation theory done with reduced order models of BWR. (author)

  12. Reduced order models, inertial manifolds, and global bifurcations: searching instability boundaries in nuclear power systems

    International Nuclear Information System (INIS)

    Suarez-Antola, Roberto; Ministerio de Industria, Energia y Mineria, Montevideo

    2011-01-01

    One of the goals of nuclear power systems design and operation is to restrict the possible states of certain critical subsystems to remain inside a certain bounded set of admissible states and state variations. In the framework of an analytic or numerical modeling process of a BWR power plant, this could imply first to find a suitable approximation to the solution manifold of the differential equations describing the stability behavior, and then a classification of the different solution types concerning their relation with the operational safety of the power plant. Inertial manifold theory gives a foundation for the construction and use of reduced order models (ROM's) of reactor dynamics to discover and characterize meaningful bifurcations that may pass unnoticed during digital simulations done with full scale computer codes of the nuclear power plant. The March-Leuba's BWR ROM is generalized and used to exemplify the analytical approach developed here. A nonlinear integral-differential equation in the logarithmic power is derived. Introducing a KBM Ansatz, a coupled set of two nonlinear ordinary differential equations is obtained. Analytical formulae are derived for the frequency of oscillation and the parameters that determine the stability of the steady states, including sub- and supercritical PAH bifurcations. A Bautin's bifurcation scenario seems possible on the power-flow plane: near the boundary of stability, a region where stable steady states are surrounded by unstable limit cycles surrounded at their turn by stable limit cycles. The analytical results are compared with recent digital simulations and applications of semi-analytical bifurcation theory done with reduced order models of BWR. (author)

  13. Understanding and controlling the step bunching instability in aqueous silicon etching

    Science.gov (United States)

    Bao, Hailing

    Chemical etching of silicon has been widely used for more than half a century in the semiconductor industry. It not only forms the basis for current wafer cleaning processes, it also serves as a powerful tool to create a variety of surface morphologies for different applications. Its potential for controlling surface morphology at the atomic scale over micron-size regions is especially appealing. In spite of its wide usage, the chemistry of silicon etching is poorly understood. Many seemingly simple but fundamental questions have not been answered. As a result, the development of new etchants and new etching protocols are based on expensive and tedious trial-and-error experiments. A better understanding of the etching mechanism would direct the rational formulation of new etchants that produce controlled etch morphologies. Particularly, micron-scale step bunches spontaneously develop on the vicinal Si(111) surface etched in KOH or other anisotropic aqueous etchants. The ability to control the size, orientation, density and regularity of these surface features would greatly improve the performance of microelectromechanical devices. This study is directed towards understanding the chemistry and step bunching instability in aqueous anisotropic etching of silicon through a combination of experimental techniques and theoretical simulations. To reveal the cause of step-bunching instability, kinetic Monte Carlo simulations were constructed based on an atomistic model of the silicon lattice and a modified kinematic wave theory. The simulations showed that inhomogeneity was the origin of step-bunching, which was confirmed through STM studies of etch morphologies created under controlled flow conditions. To quantify the size of the inhomogeneities in different etchants and to clarify their effects, a five-parallel-trench pattern was fabricated. This pattern used a nitride mask to protect most regions of the wafer; five evenly spaced etch windows were opened to the Si(110

  14. Reduced order models, inertial manifolds, and global bifurcations: searching instability boundaries in nuclear power systems

    International Nuclear Information System (INIS)

    Suarez Antola, R.

    2011-01-01

    One of the goals of nuclear power systems design and operation is to restrict the possible states of certain critical subsystems, during steady operation and during transients, to remain inside a certain bounded set of admissible states and state variations. Also, during transients, certain restrictions must be imposed on the time scale of evolution of the critical subsystem's state. A classification of the different solution types concerning their relation with the operational safety of the power plant is done by distributing the different solution types in relation with the exclusion region of the power-flow map. In the framework of an analytic or numerical modeling process of a boiling water reactor (BWR) power plant, this could imply first to find an suitable approximation to the solution manifold of the differential equations describing the stability behavior of this nonlinear system, and then a classification of the different solution types concerning their relation with the operational safety of the power plant, by distributing the different solution types in relation with the exclusion region of the power-flow map. Inertial manifold theory gives a foundation for the construction and use of reduced order models (ROM's) of reactor dynamics to discover and characterize meaningful bifurcations that may pass unnoticed during digital simulations done with full scale computer codes of the nuclear power plant. The March-Leuba's BWR ROM is used to exemplify the analytical approach developed here. The equation for excess void reactivity of this ROM is generalized. A nonlinear integral-differential equation in the logarithmic power is derived, including the generalized thermal-hydraulics feedback on the reactivity. Introducing a Krilov- Bogoliubov-Mitropolsky (KBM) ansatz with both amplitude and phase being slowly varying functions of time relative to the center period of oscillation, a coupled set of nonlinear ordinary differential equations for amplitude and phase

  15. Spatiotemporal postural control deficits are present in those with chronic ankle instability

    Directory of Open Access Journals (Sweden)

    McKeon Patrick O

    2008-06-01

    Full Text Available Abstract Background Postural control deficits have been purported to be a potential contributing factor in chronic ankle instability (CAI. Summary forceplate measures such as center of pressure velocity and area have not consistently detected postural control deficits associated with CAI. A novel measurement technique derived from the dynamical systems theory of motor control known as Time-to-boundary (TTB has shown promise in detecting deficits in postural control related to chronic ankle instability (CAI. In a previous study, TTB deficits were detected in a sample of females with CAI. The purpose of this study was to examine postural control in sample of males and females with and without CAI using TTB measures. Methods This case-control study was performed in a research laboratory. Thirty-two subjects (18 males, 14 females with self-reported CAI were recruited and matched to healthy controls. All subjects performed three, ten-second trials of single-limb stance on a forceplate with eyes open and eyes closed. Main outcome measures included the TTB absolute minimum (s, mean of TTB minima (s, and standard deviation of TTB minima (s in the anteroposterior and mediolateral directions. A series of group by gender analyses of variance were conducted to evaluate the differences in postural control for all TTB variables separately with eyes open and eyes closed. Results There were no significant group by gender interactions or gender main effects for any of the measures. There, however, significant group main effects for 4 of the 6 measures with eyes closed as the CAI group demonstrated significant deficits in comparison to the control group. There were no significant differences between groups in any of the TTB measures with eyes open. Conclusion TTB deficits were present in the CAI group compared to the control group. These deficits were detected with concurrent removal of visual input. CAI may place significantly greater constraints on the

  16. Parabolized Stability Equations analysis of nonlinear interactions with forced eigenmodes to control subsonic jet instabilities

    International Nuclear Information System (INIS)

    Itasse, Maxime; Brazier, Jean-Philippe; Léon, Olivier; Casalis, Grégoire

    2015-01-01

    Nonlinear evolution of disturbances in an axisymmetric, high subsonic, high Reynolds number hot jet with forced eigenmodes is studied using the Parabolized Stability Equations (PSE) approach to understand how modes interact with one another. Both frequency and azimuthal harmonic interactions are analyzed by setting up one or two modes at higher initial amplitudes and various phases. While single mode excitation leads to harmonic growth and jet noise amplification, controlling the evolution of a specific mode has been made possible by forcing two modes (m 1 , n 1 ), (m 2 , n 2 ), such that the difference in azimuth and in frequency matches the desired “target” mode (m 1 − m 2 , n 1 − n 2 ). A careful setup of the initial amplitudes and phases of the forced modes, defined as the “killer” modes, has allowed the minimizing of the initially dominant instability in the near pressure field, as well as its estimated radiated noise with a 15 dB loss. Although an increase of the overall sound pressure has been found in the range of azimuth and frequency analyzed, the present paper reveals the possibility to make the initially dominant instability ineffective acoustically using nonlinear interactions with forced eigenmodes

  17. Parabolized Stability Equations analysis of nonlinear interactions with forced eigenmodes to control subsonic jet instabilities

    Energy Technology Data Exchange (ETDEWEB)

    Itasse, Maxime, E-mail: Maxime.Itasse@onera.fr; Brazier, Jean-Philippe, E-mail: Jean-Philippe.Brazier@onera.fr; Léon, Olivier, E-mail: Olivier.Leon@onera.fr; Casalis, Grégoire, E-mail: Gregoire.Casalis@onera.fr [Onera - The French Aerospace Lab, F-31055 Toulouse (France)

    2015-08-15

    Nonlinear evolution of disturbances in an axisymmetric, high subsonic, high Reynolds number hot jet with forced eigenmodes is studied using the Parabolized Stability Equations (PSE) approach to understand how modes interact with one another. Both frequency and azimuthal harmonic interactions are analyzed by setting up one or two modes at higher initial amplitudes and various phases. While single mode excitation leads to harmonic growth and jet noise amplification, controlling the evolution of a specific mode has been made possible by forcing two modes (m{sub 1}, n{sub 1}), (m{sub 2}, n{sub 2}), such that the difference in azimuth and in frequency matches the desired “target” mode (m{sub 1} − m{sub 2}, n{sub 1} − n{sub 2}). A careful setup of the initial amplitudes and phases of the forced modes, defined as the “killer” modes, has allowed the minimizing of the initially dominant instability in the near pressure field, as well as its estimated radiated noise with a 15 dB loss. Although an increase of the overall sound pressure has been found in the range of azimuth and frequency analyzed, the present paper reveals the possibility to make the initially dominant instability ineffective acoustically using nonlinear interactions with forced eigenmodes.

  18. Passive control of thermoacoustic instabilities in swirl-stabilized combustion at elevated pressures

    Directory of Open Access Journals (Sweden)

    L Justin Williams

    2016-09-01

    Full Text Available In this study, a porous insert is placed at the dump plane of a swirl-stabilized lean premixed combustor to passively suppress thermoacoustic instabilities. The diffuser-shaped annular ring of porous inert material influences the turbulent flow field directly, including recirculation zones and vortical and/or shear layer structures to passively control the acoustic performance of the combustor. The porous inert material is made of silicon carbide–hafnium carbide coated, high-strength, high-temperature-resistant open-cell foam materials. In this study, the porous insert concept is investigated at above-ambient operating pressures to demonstrate its suitability for practical combustion applications. Experiments are conducted in quartz and metal combustors, without and with the porous insert while varying operating pressure, equivalence ratio, and reactant flow rate. Measurements show that the porous insert, and consequent changes in the combustor flow field, decrease the sound pressure levels at the frequency of combustion instability at all operating conditions investigated in this study. The porous insert also decreases the broadband combustion noise, i.e. the measured sound pressure levels over a wide frequency range.

  19. Feedback and Feedforward Control During Walking in Individuals With Chronic Ankle Instability.

    Science.gov (United States)

    Yen, Sheng-Che; Corkery, Marie B; Donohoe, Amy; Grogan, Maddison; Wu, Yi-Ning

    2016-09-01

    Study Design Controlled laboratory study. Background Recurrent ankle sprains associated with chronic ankle instability (CAI) occur not only in challenging sports but also in daily walking. Understanding whether and how CAI alters feedback and feedforward controls during walking may be important for developing interventions for CAI prevention or treatment. Objective To understand whether CAI is associated with changes in feedback and feedforward control when individuals with CAI are subjected to experimental perturbation during walking. Methods Twelve subjects with CAI and 12 control subjects walked on a treadmill while adapting to external loading that generated inversion perturbation at the ankle joint. Ankle kinematics around heel contact during and after the adaptation were compared between the 2 groups. Results Both healthy and CAI groups showed an increase in eversion around heel contact in early adaptation to the external loading. However, the CAI group adapted back toward the baseline, while the healthy controls showed further increase in eversion in late adaptation. When the external loading was removed in the postadaptation period, healthy controls showed an aftereffect consisting of an increase in eversion around heel contact, but the CAI group showed no aftereffect. Conclusion The results provide preliminary evidence that CAI may alter individuals' feedback and feedforward control during walking. J Orthop Sports Phys Ther 2016;46(9):775-783. Epub 5 Aug 2016. doi:10.2519/jospt.2016.6403.

  20. Control of MHD instabilities by ECCD: ASDEX Upgrade results and implications for ITER

    International Nuclear Information System (INIS)

    Zohm, H.; Gantenbein, G.; Leuterer, F.; Manini, A.; Maraschek, M.; Yu, Q.

    2007-01-01

    The requirements for control of MHD instabilities by electron cyclotron current drive (ECCD) are reviewed. It is shown that a localized current drive is needed for control of both sawteeth and neoclassical tearing modes (NTMs). In the case of NTMs, the deposition width should be smaller than the island width for efficient control. At island widths smaller than the deposition width, as is predicted to occur in ITER, theory suggests that efficient control is possible only by modulating the ECCD power in phase with the island. These predictions are experimentally confirmed in ASDEX Upgrade for NTM control. Narrow deposition has also been used to extend the operational range of NTM stabilization in ASDEX Upgrade to lower q 95 and in the improved H-mode scenario. Our results suggest that, for the ITER ECCD system, good localization of the driven current profile as well as the capability to modulate the ECCD in phase with rotating modes will be needed for efficient MHD control by ECCD

  1. Optimal control of transverse mode coupling instability based on the two particle model

    International Nuclear Information System (INIS)

    Ogata, Atsushi

    1985-01-01

    The optimal regulator design technique is applied to asymptotically stabilize the transverse mode coupling instability of a storage ring. The state equations are based on the two particle model. These are a pair of equation sets, one for the first and one for the second half of the synchrotron phase. Each set consists of first-order difference equations in vector-matrix form, with time step equal to the revolution time of the ring. Solution of the discrete Riccati equation gives the optimal gain matrix of the transverse feedback. Computer simulations are carried out to verify its effectiveness. Some modifications necessary to apply it to the real accelerator operation are made. The old methods, the classical output feedback and the reactive feedback, are interpreted from the viewpoint of the optimal control. (orig.)

  2. Hysteresis-controlled instability waves in a scale-free driven current sheet model

    Directory of Open Access Journals (Sweden)

    V. M. Uritsky

    2005-01-01

    Full Text Available Magnetospheric dynamics is a complex multiscale process whose statistical features can be successfully reproduced using high-dimensional numerical transport models exhibiting the phenomenon of self-organized criticality (SOC. Along this line of research, a 2-dimensional driven current sheet (DCS model has recently been developed that incorporates an idealized current-driven instability with a resistive MHD plasma system (Klimas et al., 2004a, b. The dynamics of the DCS model is dominated by the scale-free diffusive energy transport characterized by a set of broadband power-law distribution functions similar to those governing the evolution of multiscale precipitation regions of energetic particles in the nighttime sector of aurora (Uritsky et al., 2002b. The scale-free DCS behavior is supported by localized current-driven instabilities that can communicate in an avalanche fashion over arbitrarily long distances thus producing current sheet waves (CSW. In this paper, we derive the analytical expression for CSW speed as a function of plasma parameters controlling local anomalous resistivity dynamics. The obtained relation indicates that the CSW propagation requires sufficiently high initial current densities, and predicts a deceleration of CSWs moving from inner plasma sheet regions toward its northern and southern boundaries. We also show that the shape of time-averaged current density profile in the DCS model is in agreement with steady-state spatial configuration of critical avalanching models as described by the singular diffusion theory of the SOC. Over shorter time scales, SOC dynamics is associated with rather complex spatial patterns and, in particular, can produce bifurcated current sheets often seen in multi-satellite observations.

  3. Observations and control of beam instabilities due to higher order modes in Indus-2

    International Nuclear Information System (INIS)

    Arora, Rajiv K.; Prasad, M.; Lad, M.; Hannurkar, P.R.

    2013-01-01

    In a synchrotron radiation source (SRS), the interaction between electron beam spectra and Higher Order Modes (HOMs) of RF cavities may give rise to coupled bunch instabilities. These instabilities may limit beam current and beam lifetime. Indus-2 SRS has four RF cavities equipped with precision temperature controller of cooling system and Higher Order Mode Frequency Shifter (HOMFS) to avoid harmful HOMs. Offline (i.e. without beam) and Online (i.e. with beam) measurements, observations and analysis of HOMs have been performed. Some of the Longitudinal modes such as L1 (∼ 950 MHz), L3 (∼ 1432 MHz), L4 (∼ 1521 MHz), L5 (∼1628 MHz) were observed to be quite prominent at specific operating conditions. Based on these studies, harmful HOMs were identified and suitable methods were evolved to avoid these HOMs. Experiments were performed to achieve high beam current in Indus-2. The precision chiller temperatures and HOMFS positions were set as per theoretical estimates and were further optimized in fine steps during experiments. With the optimized settings, beam current around 200 mA at Injection energy (550 MeV) and 157 mA at 2.5 GeV has been successfully achieved. At these settings of RF cavity water temperature and HOMFS, harmful HOMs were within safe limits during regular operation of Indus-2 at 2.5 GeV/100 mA in user mode for more than one year. In this paper, important observations, analysis and experiments to avoid harmful HOMs of RF cavities are presented. (author)

  4. Genetic control of chromosome instability in Aspergillus nidulans as a means for gene amplification in eukaryotic microorganisms

    International Nuclear Information System (INIS)

    Parag, Y.; Roper, J.A.

    1975-01-01

    A haploid strain of Aspergillus nidulans carrying I-II duplication homozygous for the leaky mutation adE20 shows improved growth on minimal medium. The duplication, though more stable than disomics, still shows instability. Several methods were used for detecting genetic control of improved stability. a) visual selection, using a duplicated strain which is very unstable due to UV sensitivity, (adE20, biAl/dp yA2; uvsB). One stable strain showed a deletion (or a lethal mutation) distal to biA on the segment at the original position (on chromosome I). This deletion reduces crossing-over frequency detween the two homologous segments. As the deletion of the non-translated segment (yellow sectors) must be preceded by crossing-over, the above reduces the frequency of yellow sectors. A deletion of the translocated segment (green sectors) results in non-viability due to the deletion, and such sectors do not appear. The net result is a stable duplication involving only 12 C.O. units carrying the gene in concern. b) Suppressors of UV sensitivity (su-uvsB) were attempted using the above uvs duplicated strain. Phenotypic revertants were easily obtained, but all were back mutations at the uvsB locus. c) Mutations for UV resistance higher than that of the wild type were not obtained, in spite of the strong selective pressure inserted. d) Recombination deficient mutations (rec), six altogether, all uvs + , did not have any effect on stability. (orig.) [de

  5. Altered neuromuscular control and ankle joint kinematics during walking in subjects with functional instability of the ankle joint.

    Science.gov (United States)

    Delahunt, Eamonn; Monaghan, Kenneth; Caulfield, Brian

    2006-12-01

    The ankle joint requires very precise neuromuscular control during the transition from terminal swing to the early stance phase of the gait cycle. Altered ankle joint arthrokinematics and muscular activity have been cited as potential factors that may lead to an inversion sprain during the aforementioned time periods. However, to date, no study has investigated patterns of muscle activity and 3D joint kinematics simultaneously in a group of subjects with functional instability compared with a noninjured control group during these phases of the gait cycle. To compare the patterns of lower limb 3D joint kinematics and electromyographic activity during treadmill walking in a group of subjects with functional instability with those observed in a control group. Controlled laboratory study. Three-dimensional angular velocities and displacements of the hip, knee, and ankle joints, as well as surface electromyography of the rectus femoris, peroneus longus, tibialis anterior, and soleus muscles, were recorded simultaneously while subjects walked on a treadmill at a velocity of 4 km/h. Before heel strike, subjects with functional instability exhibited a decrease in vertical foot-floor clearance (12.62 vs 22.84 mm; P joint before, at, and immediately after heel strike (1.69 degrees , 2.10 degrees , and -0.09 degrees vs -1.43 degrees , -1.43 degrees , and -2.78 degrees , respectively [minus value = eversion]; P < .05) compared with controls. Subjects with functional instability were also observed to have an increase in peroneus longus integral electromyography during the post-heel strike time period (107.91%.millisecond vs 64.53%.millisecond; P < .01). The altered kinematics observed in this study could explain the reason subjects with functional instability experience repeated episodes of ankle inversion injury in situations with only slight or no external provocation. It is hypothesized that the observed increase in peroneus longus activity may be the result of a change in

  6. Tectonics control over instability of volcanic edifices in transtensional tectonic regimes

    Science.gov (United States)

    Norini, G.; Capra, L.; Lagmay, A. M. F.; Manea, M.; Groppelli, G.

    2009-04-01

    We present the results of analogue modeling designed to investigate the interactions between volcanic edifices and transtensional basement faulting. Three sets of experiments were run to account for three examples of stratovolcanoes in active transtensive tectonics regimes, the Nevado de Toluca and Jocotitlan volcanoes in Mexico, and the Mayon volcano in the Philippines. All these volcanoes show different behavior and relationship among volcanism, instability of the volcanic edifice, and basement tectonics. Field geological and structural data gave the necessary constrains to the models. The modeling apparatus consisted of a sand cone on a sheared basal layer. Injections of vegetable oil were used to model the rising of magma inside the deformed analogue cones. Set 1: In the case of a volcano directly on top of a basal transtensive shear producing a narrow graben, as observed on the Nevado de Toluca volcano, the analogue models reveal a strong control of the basement faulting on the magma migration path and the volcano instability. Small lateral collapses are directed parallel to the basal shear and affect a limited sector of the cone. Set 2: If the graben generated by transtensive tectonics is bigger in respect to the volcanic edifice and the volcano sits on one boundary fault, as in the case of Mayon volcano, the combined normal and transcurrent movements of the analogue basement fault generate a sigmoidal structure in the sand cone, inducing major sector collapses directed at approx 45° relative to the basement shear toward the downthrown block. Set 3: For volcanoes located near major transtensive faults, as the Jocotitlan volcano, analogue modelling shows an important control of the regional tectonics on the geometry of the fractures and migration paths of magma inside the cone. These structures render unstable the flanks of the volcano and promote sector collapses perpendicular to the basement shear and directed toward the graben formed by the transtensive

  7. Deviations in gait metrics in patients with chronic ankle instability: a case control study.

    Science.gov (United States)

    Gigi, Roy; Haim, Amir; Luger, Elchanan; Segal, Ganit; Melamed, Eyal; Beer, Yiftah; Nof, Matityahu; Nyska, Meir; Elbaz, Avi

    2015-01-01

    Gait metric alterations have been previously reported in patients suffering from chronic ankle instability (CAI). Previous studies of gait in this population have been comprised of relatively small cohorts, and the findings of these studies are not uniform. The objective of the present study was to examine spatiotemporal gait metrics in patients with CAI and examine the relationship between self-reported disease severity and the magnitude of gait abnormalities. Forty-four patients with CAI were identified and compared to 53 healthy controls. Patients were evaluated with spatiotemporal gait analysis via a computerized mat and with the Short Form (SF) - 36 health survey. Patients with CAI were found to walk with approximately 16% slower walking velocity, 9% lower cadence and approximately 7% lower step length. Furthermore, the base of support, during walking, in the CAI group was approximately 43% wider, and the single limb support phase was 3.5% shorter compared to the control group. All of the SF-36 8-subscales, as well as the SF-36 physical component summary and SF-36 mental component summary, were significantly lower in patients with CAI compared to the control group. Finally, significant correlations were found between most of the objective gait measures and the SF-36 mental component summary and SF-36 physical component summary. The results outline a gait profile for patients suffering from CAI. Significant differences were found in most spatiotemporal gait metrics. An important finding was a significantly wider base of support. It may be speculated that these gait alterations may reflect a strategy to deal with imbalance and pain. These findings suggest the usefulness of gait metrics, alongside with the use of self-evaluation questionnaires, in assessing disease severity of patients with CAI.

  8. Reflex muscle contraction in anterior shoulder instability.

    Science.gov (United States)

    Wallace, D A; Beard, D J; Gill, R H; Eng, B; Carr, A J

    1997-01-01

    Reduced proprioception may contribute to recurrent anterior shoulder instability. Twelve patients with unilateral shoulder instability were investigated for evidence of deficient proprioception with an activated pneumatic cylinder and surface electromyography electrodes; the contralateral normal shoulder was used as a control. The latency between onset of movement and the detection of muscle contraction was used as an index of proprioception. No significant difference in muscle contraction latency was detected between the stable and unstable shoulders, suggesting that there was no significant defect in muscular reflex activity. This study does not support the use proprioception-enhancing physiotherapy in the treatment of posttraumatic anterior shoulder instability.

  9. Reducing feedback requirements of workload control

    NARCIS (Netherlands)

    Henrich, Peter; Land, Martin; van der Zee, Durk; Gaalman, Gerard

    2004-01-01

    The workload control concept is known as a robust shop floor control concept. It is especially suited for the dynamic environment of small- and medium-sized enterprises (SMEs) within the make-to-order sector. Before orders are released to the shop floor, they are collected in an ‘order pool’. To

  10. Reducing prediction uncertainty of weather controlled systems

    NARCIS (Netherlands)

    Doeswijk, T.G.

    2007-01-01

    In closed agricultural systems the weather acts both as a disturbance and as a resource. By using weather forecasts in control strategies the effects of disturbances can be minimized whereas the resources can be utilized. In this situation weather forecast uncertainty and model based control are

  11. Patients with triangular fibrocartilage complex injuries and distal radioulnar joint instability have reduced rotational torque in the forearm.

    Science.gov (United States)

    Andersson, J K; Axelsson, P; Strömberg, J; Karlsson, J; Fridén, J

    2016-09-01

    A total of 20 patients scheduled for wrist arthroscopy, all with clinical signs of rupture to the triangular fibrocartilage complex and distal radioulnar joint instability, were tested pre-operatively by an independent observer for strength of forearm rotation. During surgery, the intra-articular pathology was documented by photography and also subsequently individually analysed by another independent hand surgeon. Arthroscopy revealed a type 1-B injury to the triangular fibrocartilage complex in 18 of 20 patients. Inter-rater reliability between the operating surgeon and the independent reviewer showed absolute agreement in all but one patient (95%) in terms of the injury to the triangular fibrocartilage complex and its classification. The average pre-operative torque strength was 71% of the strength of the non-injured contralateral side in pronation and supination. Distal radioulnar joint instability with an arthroscopically verified injury to the triangular fibrocartilage complex is associated with a significant loss of both pronation and supination torque. Case series, Level IV. © The Author(s) 2015.

  12. Government control of markets of financial services of Ukraine in conditions of macroeconomic instability

    Directory of Open Access Journals (Sweden)

    Ігор Юрійович Мельников

    2015-05-01

    Full Text Available An essence of financial services market of Ukraine is considered in the article. The mechanism and features of state regulation of financial services market in the context of macroeconomic instability are determined, the fundamentals of the theory of regulation of market economy and segments of the financial market of Ukraine are determined

  13. Adaptive and Nonadaptive Feedback Control of Global Instabilities with Application to a Heated 2-D Jet

    Science.gov (United States)

    1992-04-01

    Hannemann & Oertel (1989) and many others. If the the mean flow is weakly nonparallel, i.e. evolves slowly on the scale of a typical instability wave... HANNEMANN , K. & OERTEL, H. Jr. 1989 Numerical simulation of the absolutely and convectively unstable wake. J. Fluid Mech. 199, 55-88. HUERRE, P. & MONKEWITZ

  14. Active Control of Combustion Instability in a Ramjet Using Large-Eddy Simulations

    Science.gov (United States)

    1992-09-01

    dobim ft n ban, fl" cowhader.~~ -Mpo with mainly bo qvco sp a n mod to model Aftbous! the chcise Of beatle (AL. p adthbe the bjadwt. 21w ,eelhl %i...INTEGRATED, INC. --21414 - 68th Avenue South Kent, Washington 98032 (206) 872-9500 DISCLAIMER NOTICE THIS DOCUMENT IS BEST QUALITY AVAILABLE. THE COPY...ing nonlinear interactions among acoustic waves, vortex motion and unsteady heat release. Typically, the instability manifests itself as a large

  15. Neutrino-driven supernovae: An accretion instability in a nuclear physics controlled environment

    International Nuclear Information System (INIS)

    Janka, H.-T.; Buras, R.; Kitaura Joyanes, F.S.; Marek, A.; Rampp, M.; Scheck, L.

    2005-01-01

    New simulations demonstrate that low-mode, nonradial hydrodynamic instabilities of the accretion shock help starting hot-bubble convection in supernovae and thus support explosions by the neutrino-heating mechanism. The prevailing conditions depend on the high-density equation of state which governs stellar core collapse, core bounce, and neutron star formation. Tests of this sensitivity to nuclear physics variations are shown for spherically symmetric models. Implications of current explosion models for r-process nucleosynthesis are addressed

  16. Spatial flux instabilities, and their control in the graphite gas power reactors; Les instabilites spatiales du flux et leur controle dans les reacteurs de puissance graphite-gaz

    Energy Technology Data Exchange (ETDEWEB)

    Cailly, J L [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    Radial-azimuthal and axial spatial flux instabilities in graphite-gas reactors are studied by means of an analytical approach. Results are checked with those which are given by two dimensional (r, z and r, {theta}) kinetic models programmed for an IBM 7094 computer. At least, conclusions on the control of instabilities obtained from these models are reported. (author) [French] Les instabilites spatiales du flux dans les reacteurs graphite-gaz, radiales et azimutales d'une part, axiales d'autre part, sont etudiees au moyen d'une formulation analytique. Les resultats sont confrontes avec ceux que fournissent des modeles cinetiques a deux dimensions (r, z et r, {theta}) programmes sur IBM 7094. On donne enfin les conclusions relatives au controle de ces instabilites que ces modeles ont permis de degager. (auteur)

  17. Virtual Reality Telerehabilitation for Postural Instability in Parkinson’s Disease: A Multicenter, Single-Blind, Randomized, Controlled Trial

    Directory of Open Access Journals (Sweden)

    Marialuisa Gandolfi

    2017-01-01

    Full Text Available Introduction. Telerehabilitation enables patients to access remote rehabilitation services for patient-physiotherapist videoconferencing in their own homes. Home-based virtual reality (VR balance training has been shown to reduce postural instability in patients with Parkinson’s disease (PD. The primary aim was to compare improvements in postural stability after remotely supervised in-home VR balance training and in-clinic sensory integration balance training (SIBT. Methods. In this multicenter study, 76 PD patients (modified Hoehn and Yahr stages 2.5–3 were randomly assigned to receive either in-home VR telerehabilitation (n=38 or in-clinic SIBT (n=38 in 21 sessions of 50 minutes each, 3 days/week for 7 consecutive weeks. VR telerehabilitation consisted of graded exergames using the Nintendo Wii Fit system; SIBT included exercises to improve postural stability. Patients were evaluated before treatment, after treatment, and at 1-month follow-up. Results. Analysis revealed significant between-group differences in improvement on the Berg Balance Scale for the VR telerehabilitation group (p=0.04 and significant Time × Group interactions in the Dynamic Gait Index (p=0.04 for the in-clinic group. Both groups showed differences in all outcome measures over time, except for fall frequency. Cost comparison yielded between-group differences in treatment and equipment costs. Conclusions. VR is a feasible alternative to in-clinic SIBT for reducing postural instability in PD patients having a caregiver.

  18. Adaptative control of aero-acoustic instabilities. Application to propulsion systems; Controle adaptatif des instabilites aeroacoustiques. Application aux systemes de propulsion

    Energy Technology Data Exchange (ETDEWEB)

    Mettenleiter, M.

    2000-02-15

    This work treats active adaptive control of aero-acoustic instabilities. In particular, we are interested in an application to solid propellant rockets. The study is part of the research program ASSM coordinated by CNES and ONERA and the aim is to increase the performance of the P230 segmented solid propellant boosters of the Ariane 5 rocket. The work has been carried out in collaboration with other partners of this program. The main objective of this study is the development of control algorithms, able to diminish low frequency instabilities encountered in propulsion systems. First, the instability phenomenon is analyzed in a simplified experimental setup and similarity is shown with instabilities observed in real propulsion systems. This study enables us to conceive adaptive control strategies, which have been tested on three different levels: - In a simplified dynamical simulation; - During an experimental study; - Using full numerical simulations. The three levels of application made it possible to study the behaviour of the different control strategies. We could show that the actuator signal modifies the behaviour of the system on the acoustic level. But as there is a strong interaction between the pressure fluctuations and the hydrodynamic behaviour, the flow structure is also modified by active control. This behaviour corresponds to the simplified model of the phenomenon, which has been used to define the control algorithms. The control action 'at the noise source' makes it possible to distinguish this kind of algorithms from schemes based on the anti-noise principle. After this first part, where we showed the feasibility of control, we particularly considered algorithms which can act in an unknown environment. The information about the system behaviour. which is necessary for convergence of the controller is now obtained in parallel during control. An identification off-line, used at the beginning of the research, is no longer necessary. Self

  19. On the granular fingering instability: controlled triggering in laboratory experiments and numerical simulations

    Science.gov (United States)

    Vriend, Nathalie; Tsang, Jonny; Arran, Matthew; Jin, Binbin; Johnsen, Alexander

    2017-11-01

    When a mixture of small, smooth particles and larger, coarse particles is released on a rough inclined plane, the initial uniform front may break up in distinct fingers which elongate over time. This fingering instability is sensitive to the unique arrangement of individual particles and is driven by granular segregation (Pouliquen et al., 1997). Variability in initial conditions create significant limitations for consistent experimental and numerical validation of newly developed theoretical models (Baker et al., 2016) for finger formation. We present an experimental study using a novel tool that sets the initial fingering width of the instability. By changing this trigger width between experiments, we explore the response of the avalanche breakup to perturbations of different widths. Discrete particle simulations (using MercuryDPM, Thornton et al., 2012) are conducted under a similar setting, reproducing the variable finger width, allowing validation between experiments and numerical simulations. A good agreement between simulations and experiments is obtained, and ongoing theoretical work is briefly introduced. NMV acknowledges the Royal Society Dorothy Hodgkin Research Fellowship.

  20. Plasma instability control toward high fluence, high energy x-ray continuum source

    Science.gov (United States)

    Poole, Patrick; Kirkwood, Robert; Wilks, Scott; Blue, Brent

    2017-10-01

    X-ray source development at Omega and NIF seeks to produce powerful radiation with high conversion efficiency for material effects studies in extreme fluence environments. While current K-shell emission sources can achieve tens of kJ on NIF up to 22 keV, the conversion efficiency drops rapidly for higher Z K-alpha energies. Pulsed power devices are efficient generators of MeV bremsstrahlung x-rays but are unable to produce lower energy photons in isolation, and so a capability gap exists for high fluence x-rays in the 30 - 100 keV range. A continuum source under development utilizes instabilities like Stimulated Raman Scattering (SRS) to generate plasma waves that accelerate electrons into high-Z converter walls. Optimizing instabilities using existing knowledge on their elimination will allow sufficiently hot and high yield electron distributions to create a superior bremsstrahlung x-ray source. An Omega experiment has been performed to investigate the optimization of SRS and high energy x-rays using Au hohlraums with parylene inner lining and foam fills, producing 10× greater x-ray yield at 50 keV than conventional direct drive experiments on the facility. Experiment and simulation details on this campaign will be presented. This work was performed under the auspices of the US DoE by LLNL under Contract No. DE-AC52-07NA27344.

  1. Genomic instability following irradiation

    International Nuclear Information System (INIS)

    Hacker-Klom, U.B.; Goehde, W.

    2001-01-01

    Ionising irradiation may induce genomic instability. The broad spectrum of stress reactions in eukaryontic cells to irradiation complicates the discovery of cellular targets and pathways inducing genomic instability. Irradiation may initiate genomic instability by deletion of genes controlling stability, by induction of genes stimulating instability and/or by activating endogeneous cellular viruses. Alternatively or additionally it is discussed that the initiation of genomic instability may be a consequence of radiation or other agents independently of DNA damage implying non nuclear targets, e.g. signal cascades. As a further mechanism possibly involved our own results may suggest radiation-induced changes in chromatin structure. Once initiated the process of genomic instability probably is perpetuated by endogeneous processes necessary for proliferation. Genomic instability may be a cause or a consequence of the neoplastic phenotype. As a conclusion from the data available up to now a new interpretation of low level radiation effects for radiation protection and in radiotherapy appears useful. The detection of the molecular mechanisms of genomic instability will be important in this context and may contribute to a better understanding of phenomenons occurring at low doses <10 cSv which are not well understood up to now. (orig.)

  2. Reduced Attitude Control of a Robotic Underwater Vehicle

    Directory of Open Access Journals (Sweden)

    Bláha Lukáš

    2017-01-01

    Full Text Available This paper deals with stabilization and reduced attitude control of a robotic underwater vehicle. The vehicle is assumed to be able to perform a full stable rotations around all axes in underwater space, that is why the standard bottom-heavy structure is not used. The system preferably uses a vectored-thrust arrangement and is built as an overactuated system, which enables to gain a better robustness and guarantees a stable controlled motion even if some thruster suddenly stop working. Because the heading angle cannot be measured, the reduced attitude control strategy is designed and the stability of reduced state of the system is proved using perturbation method.

  3. COMPARISON OF SENSORS FOR RESISTIVE WALL MODE FEEDBACK CONTROL. MILESTONE No.145 ''CONTAINING PLASMA INSTABILITIES WITH METAL WALLS''

    International Nuclear Information System (INIS)

    STRAIT, E.J.; CHU, M.S.; GAROFALO, A.M.; LAHAYE, R.J.; OKABAYASHI, M.; REIMERDES, H.; SCOVILLE, J.T.; TURNBULL, A.D.

    2002-01-01

    OAK A271 COMPARISON OF SENSORS FOR RESISTIVE WALL MODE FEEDBACK CONTROL MILESTONE No.145 CONTAINING PLASMA INSTABILITIES WITH METAL WALLS. The most serious instabilities in the tokamak are those described by ideal magneto-hydrodynamic theory. These modes limit the stable operating space of the tokamak. The ideal MHD calculations predict the stable operating space of the tokamak may be approximately doubled when a perfectly conducting metal wall is placed near the plasma boundary, compared to the case with no wall (free boundary). The unstable mode distortions of the plasma column cannot bulge out through a perfectly conducting wall. However, real walls have finite conductivity and when plasmas are operated in the regime between the free boundary stability limit and the perfectly conducting wall limit, the unstable mode encountered in that case the resistive wall mode, can leak out through the metal wall, allowing the mode to keep slowly growing. The slow growth affords the possibility of feedback stabilizing this mode with external coils. DIII-D is making good progress in such feedback stabilization research and in 2002 will use an improved set of mode sensors inside the vacuum vessel and closer to the plasma surface which are expected theoretically to improve the ability to stabilize the resistive wall mode

  4. Physical understanding of the instability spectrum and the feedback control of resistive wall modes in reversed field pinch

    International Nuclear Information System (INIS)

    Wang, Z.R.; Guo, S.C.

    2011-01-01

    The cylindrical MHD model integrated with a feedback system is applied to the study of resistive wall mode (RWM) in reversed field pinch (RFP) plasmas. The model takes into account the compressibility, longitudinal flow, viscosity and resistive wall with a finite thickness. The study, via both analytical and numerical analyses, provides a physical understanding on the following subjects: firstly, on the nature of the instability spectrum of the RWM observed in RFP plasmas; specifically, the growth rates of the two groups of the RWMs (internally non-resonant and externally non-resonant) have opposite dependence on the variation of the field reversal. Secondly, on the response of the unstable plasmas to the feedback control in RFPs, the mode behaviour in plasmas under the feedback is clarified and discussed in detail. Finally, the linear solutions of time evolution of RWM instability in various feedback scenarios are given. The effects of the wall proximity, the sensor location and the system response time are discussed, respectively.

  5. The effectiveness of foot orthotics in improving postural control in individuals with chronic ankle instability: a critically appraised topic.

    Science.gov (United States)

    Gabriner, Michael L; Braun, Brittany A; Houston, Megan N; Hoch, Matthew C

    2015-02-01

    Chronic ankle instability (CAI) is a condition commonly experienced by physically active individuals. It has been suggested that foot orthotics may increase a CAI patient's postural control. For patients with CAI, is there evidence to suggest that an orthotic intervention will help improve postural control? The literature was searched for studies of level 2 evidence or higher that investigated the effects of foot orthotics on postural control in patients with CAI. The search of the literature produced 5 possible studies for inclusion; 2 studies met the inclusion criteria and were included. One randomized controlled trial and 1 outcomes study were included. Foot orthotics appear to be effective at improving postural control in patients with CAI. There is moderate evidence to support the use of foot orthotics in the treatment of CAI to help improve postural control. There is grade B evidence that foot orthotics help improve postural control in people with CAI. The Centre of Evidence Based Medicine recommends a grade of B for level 2 evidence with consistent findings.

  6. Periodic equivalence ratio modulation method and apparatus for controlling combustion instability

    Science.gov (United States)

    Richards, George A.; Janus, Michael C.; Griffith, Richard A.

    2000-01-01

    The periodic equivalence ratio modulation (PERM) method and apparatus significantly reduces and/or eliminates unstable conditions within a combustion chamber. The method involves modulating the equivalence ratio for the combustion device, such that the combustion device periodically operates outside of an identified unstable oscillation region. The equivalence ratio is modulated between preselected reference points, according to the shape of the oscillation region and operating parameters of the system. Preferably, the equivalence ratio is modulated from a first stable condition to a second stable condition, and, alternatively, the equivalence ratio is modulated from a stable condition to an unstable condition. The method is further applicable to multi-nozzle combustor designs, whereby individual nozzles are alternately modulated from stable to unstable conditions. Periodic equivalence ratio modulation (PERM) is accomplished by active control involving periodic, low frequency fuel modulation, whereby low frequency fuel pulses are injected into the main fuel delivery. Importantly, the fuel pulses are injected at a rate so as not to affect the desired time-average equivalence ratio for the combustion device.

  7. Tearing instabilities in turbulence

    International Nuclear Information System (INIS)

    Ishizawa, A.; Nakajima, N.

    2009-01-01

    Full text: Effects of micro-turbulence on tearing instabilities are investigated by numerically solving a reduced set of two-fluid equations. Micro-turbulence excites both large-scale and small-scale Fourier modes through energy transfer due to nonlinear mode coupling. The energy transfer to large scale mode does not directly excite tearing instability but it gives an initiation of tearing instability. When tearing instability starts to grow, the excited small scale mode plays an important role. The mixing of magnetic flux by micro-turbulence is the dominant factor of non-ideal MHD effect at the resonant surface and it gives rise to magnetic reconnection which causes tearing instability. Tearing instabilities were investigated against static equilibrium or flowing equilibrium so far. On the other hand, the recent progress of computer power allows us to investigate interactions between turbulence and coherent modes such as tearing instabilities in magnetically confined plasmas by means of direct numerical simulations. In order to investigate effects of turbulence on tearing instabilities we consider a situation that tearing mode is destabilized in a quasi-equilibrium including micro-turbulence. We choose an initial equilibrium that is unstable against kinetic ballooning modes and tearing instabilities. Tearing instabilities are current driven modes and thus they are unstable for large scale Fourier modes. On the other hand kinetic ballooning modes are unstable for poloidal Fourier modes that are characterized by ion Larmor radius. The energy of kinetic ballooning modes spreads over wave number space through nonlinear Fourier mode coupling. We present that micro-turbulence affects tearing instabilities in two different ways by three-dimensional numerical simulation of a reduced set of two-fluid equations. One is caused by energy transfer to large scale modes, the other is caused by energy transfer to small scale modes. The former is the excitation of initial

  8. Assessment of Relationships Between Joint Motion Quality and Postural Control in Patients With Chronic Ankle Joint Instability.

    Science.gov (United States)

    Bączkowicz, Dawid; Falkowski, Krzysztof; Majorczyk, Edyta

    2017-08-01

    Study Design Controlled laboratory study, cross-sectional. Background Lateral ankle sprains are among the most common injuries encountered during athletic participation. Following the initial injury, there is an alarmingly high risk of reinjury and development of chronic ankle instability (CAI), which is dependent on a combination of factors, including sensorimotor deficits and changes in the biomechanical environment of the ankle joint. Objective To evaluate CAI-related disturbances in arthrokinematic motion quality and postural control and the relationships between them. Methods Sixty-three male subjects (31 with CAI and 32 healthy controls) were enrolled in the study. For arthrokinematic motion quality analysis, the vibroarthrographic signals were collected during ankle flexion/extension motion using an acceleration sensor and described by variability (variance of mean squares [VMS]), amplitude (mean of 4 maximal and 4 minimal values [R4]), and frequency (vibroarthrographic signal bands of 50 to 250 Hz [P1] and 250 to 450 Hz [P2]) parameters. Using the Biodex Balance System, single-leg dynamic balance was measured by overall, anteroposterior, and mediolateral stability indices. Results Values of vibroarthrographic parameters (VMS, R4, P1 and P2) were significantly higher in the CAI group than those in the control group (Pankle arthrokinematic motion and postural control were present. Therefore, physical therapy interventions focused on improving ankle neuromuscular control and arthrokinematic function are necessary in CAI patient care. J Orthop Sports Phys Ther 2017;47(8):570-577. Epub 4 Nov 2016. doi:10.2519/jospt.2017.6836.

  9. Neuromechanical Control for Dynamic Bipedal Walking with Reduced Impact Forces

    DEFF Research Database (Denmark)

    Widenka, Johannes; Xiong, Xiaofeng; Matthias Braun, Jan

    2016-01-01

    Human walking emerges from an intricate interaction of nervous and musculoskeletal systems. Inspired by this principle, we integrate neural control and muscle-like mechanisms to achieve neuromechanical control of the biped robot RunBot. As a result, the neuromechanical controller enables RunBot t......Bot to perform more human-like walking and reduce impact force during walking, compared to original neural control. Moreover, it also generates adaptive joint motions of RunBot; thereby allowing it to deal with different terrains...

  10. Carpal instability

    International Nuclear Information System (INIS)

    Schmitt, R.; Froehner, S.; Coblenz, G.; Christopoulos, G.

    2006-01-01

    This review addresses the pathoanatomical basics as well as the clinical and radiological presentation of instability patterns of the wrist. Carpal instability mostly follows an injury; however, other diseases, like CPPD arthropathy, can be associated. Instability occurs either if the carpus is unable to sustain physiologic loads (''dyskinetics'') or suffers from abnormal motion of its bones during movement (''dyskinematics''). In the classification of carpal instability, dissociative subcategories (located within proximal carpal row) are differentiated from non-dissociative subcategories (present between the carpal rows) and combined patterns. It is essential to note that the unstable wrist initially does not cause relevant signs in standard radiograms, therefore being ''occult'' for the radiologic assessment. This paper emphasizes the high utility of kinematographic studies, contrast-enhanced magnetic resonance imaging (MRI) and MR arthrography for detecting these predynamic and dynamic instability stages. Later in the natural history of carpal instability, static malalignment of the wrist and osteoarthritis will develop, both being associated with significant morbidity and disability. To prevent individual and socio-economic implications, the handsurgeon or orthopedist, as well as the radiologist, is challenged for early and precise diagnosis. (orig.)

  11. Controllability study of EAST plasma vertical instability and improvement in future

    Energy Technology Data Exchange (ETDEWEB)

    Liu, L., E-mail: liulei@ipp.ac.cn [University of Science and Technology of China, Hefei (China); Institute of Plasma Physics, Chinese Academy of Sciences, Hefei (China); Xiao, B.J., E-mail: bjxiao@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei (China); University of Science and Technology of China, Hefei (China); Humphreys, D.A., E-mail: dave.humphreys@gat.com [General Atomics, PO Box 85608, San Diego, CA 92186-5608 (United States); Luo, Z.P., E-mail: zhpluo@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei (China); Chen, S.L., E-mail: slchen@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei (China)

    2014-05-15

    Highlights: • The discontinuous passive plate model is developed and verified by experiment. • The power supply upgrade requirements for VDE control are evaluated. • We investigate efficacy of internal control coil location for VDE control. • Maximum controllable vertical displacement experiments are done. • EAST VDE controllability is roughly given by VDE experiments. - Abstract: In order to enhance control speed, each up/down Cu passive plate in EAST is cut into 8 pieces. These discontinuous plate segments are still connected to the inner vacuum vessel by steel supporting legs. A model of this plate segments-vessel-supporting leg loop is developed and verified by EAST vertical displacement event (VDE) experiments. The internal coil (IC) power supply requirements for VDE control are also evaluated. In particularly, we investigate the efficacy of internal control coil location to minimize the power supply capability. The IC power supply upgrade requirements for the optimized location and actual location are discussed. VDE experiments to evaluate maximum controllable vertical displacement (dZmax) were done with varying elongation and resulting EAST vertical controllability estimates are summarized here. These experimental results verified previous simulation results that present IC power supply capacity cannot provide robust vertical control.

  12. Controllability study of EAST plasma vertical instability and improvement in future

    International Nuclear Information System (INIS)

    Liu, L.; Xiao, B.J.; Humphreys, D.A.; Luo, Z.P.; Chen, S.L.

    2014-01-01

    Highlights: • The discontinuous passive plate model is developed and verified by experiment. • The power supply upgrade requirements for VDE control are evaluated. • We investigate efficacy of internal control coil location for VDE control. • Maximum controllable vertical displacement experiments are done. • EAST VDE controllability is roughly given by VDE experiments. - Abstract: In order to enhance control speed, each up/down Cu passive plate in EAST is cut into 8 pieces. These discontinuous plate segments are still connected to the inner vacuum vessel by steel supporting legs. A model of this plate segments-vessel-supporting leg loop is developed and verified by EAST vertical displacement event (VDE) experiments. The internal coil (IC) power supply requirements for VDE control are also evaluated. In particularly, we investigate the efficacy of internal control coil location to minimize the power supply capability. The IC power supply upgrade requirements for the optimized location and actual location are discussed. VDE experiments to evaluate maximum controllable vertical displacement (dZmax) were done with varying elongation and resulting EAST vertical controllability estimates are summarized here. These experimental results verified previous simulation results that present IC power supply capacity cannot provide robust vertical control

  13. Percutaneous cannulated screw fixation of sacral fractures and sacroiliac joint disruptions with CT-controlled guidewires performed by interventionalists: single center experience in treating posterior pelvic instability.

    Science.gov (United States)

    Fischer, Sebastian; Vogl, Thomas J; Marzi, Ingo; Zangos, Stephan; Wichmann, Julian L; Scholtz, Jan-Erik; Mack, Martin G; Schmidt, Sven; Eichler, Katrin

    2015-02-01

    The purpose of our study was to evaluate minimally invasive sacroiliac screw fixation for treatment of posterior pelvic instability with the help of CT controlled guidewires, assess its accuracy, safety and effectiveness, and discuss potential pitfalls. 100 guidewires and hollow titan screws were inserted in 38 patients (49.6±19.5 years) suffering from 35 sacral fractures and/or 16 sacroiliac joint disruptions due to 33 (poly-)traumatic, 2 osteoporotic and 1 post-infectious conditions. The guidewire and screw positions were analyzed in multiplanar reconstructions. The mean minimal distance between guidewire and adjacent neural foramina was 4.5±2.01mm, with a distinctly higher precision in S1 than S2. Eight guidewires showed cortical contacts, resulting in a total of 2% mismatched screws with subsequent wall violation. The fracture gaps were reduced from 3.6±0.53mm to 1.2±0.54mm. During follow-up 3 cases of minor iatrogenic sacral impaction (<5mm) due to the bolting and 2 cases of screw loosening were observed. Interventional time was 84.0min with a mean of 2.63 screws per patient whilst acquiring a mean of 93.7 interventional CT-images (DLP 336.7mGycm). The treatment of posterior pelvic instability with a guidewire-based screw insertion technique under CT-imaging results in a very high accuracy and efficacy with a low complication rate. Careful attention should be drawn to radiation levels. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  14. Percutaneous cannulated screw fixation of sacral fractures and sacroiliac joint disruptions with CT-controlled guidewires performed by interventionalists: Single center experience in treating posterior pelvic instability

    International Nuclear Information System (INIS)

    Fischer, Sebastian; Vogl, Thomas J.; Marzi, Ingo; Zangos, Stephan; Wichmann, Julian L.; Scholtz, Jan-Erik; Mack, Martin G.; Schmidt, Sven; Eichler, Katrin

    2015-01-01

    Highlights: • Minimally invasive sacroiliac screw fixation can be performed under CT-imaging. • Guidewires help in precise placement of cannulated sacroiliac screw. • Only a diminishing rate of misplacements can be seen. • The method appears to be a safe and very accurate procedure. - Abstract: Objective: The purpose of our study was to evaluate minimally invasive sacroiliac screw fixation for treatment of posterior pelvic instability with the help of CT controlled guidewires, assess its accuracy, safety and effectiveness, and discuss potential pitfalls. Methods: 100 guidewires and hollow titan screws were inserted in 38 patients (49.6 ± 19.5 years) suffering from 35 sacral fractures and/or 16 sacroiliac joint disruptions due to 33 (poly-)traumatic, 2 osteoporotic and 1 post-infectious conditions. The guidewire and screw positions were analyzed in multiplanar reconstructions. Results: The mean minimal distance between guidewire and adjacent neural foramina was 4.5 ± 2.01 mm, with a distinctly higher precision in S1 than S2. Eight guidewires showed cortical contacts, resulting in a total of 2% mismatched screws with subsequent wall violation. The fracture gaps were reduced from 3.6 ± 0.53 mm to 1.2 ± 0.54 mm. During follow-up 3 cases of minor iatrogenic sacral impaction (<5 mm) due to the bolting and 2 cases of screw loosening were observed. Interventional time was 84.0 min with a mean of 2.63 screws per patient whilst acquiring a mean of 93.7 interventional CT-images (DLP 336.7 mGy cm). Conclusions: The treatment of posterior pelvic instability with a guidewire-based screw insertion technique under CT-imaging results in a very high accuracy and efficacy with a low complication rate. Careful attention should be drawn to radiation levels

  15. Percutaneous cannulated screw fixation of sacral fractures and sacroiliac joint disruptions with CT-controlled guidewires performed by interventionalists: Single center experience in treating posterior pelvic instability

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Sebastian, E-mail: sebastian.fischer@kgu.de [Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Vogl, Thomas J. [Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Marzi, Ingo [Department of Trauma, Hand and Reconstructive Surgery, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Zangos, Stephan; Wichmann, Julian L.; Scholtz, Jan-Erik; Mack, Martin G. [Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Schmidt, Sven [Orthopaedic University Hospital Friedrichsheim, Marienburgstraße, 260528 Frankfurt (Germany); Eichler, Katrin [Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany)

    2015-02-15

    Highlights: • Minimally invasive sacroiliac screw fixation can be performed under CT-imaging. • Guidewires help in precise placement of cannulated sacroiliac screw. • Only a diminishing rate of misplacements can be seen. • The method appears to be a safe and very accurate procedure. - Abstract: Objective: The purpose of our study was to evaluate minimally invasive sacroiliac screw fixation for treatment of posterior pelvic instability with the help of CT controlled guidewires, assess its accuracy, safety and effectiveness, and discuss potential pitfalls. Methods: 100 guidewires and hollow titan screws were inserted in 38 patients (49.6 ± 19.5 years) suffering from 35 sacral fractures and/or 16 sacroiliac joint disruptions due to 33 (poly-)traumatic, 2 osteoporotic and 1 post-infectious conditions. The guidewire and screw positions were analyzed in multiplanar reconstructions. Results: The mean minimal distance between guidewire and adjacent neural foramina was 4.5 ± 2.01 mm, with a distinctly higher precision in S1 than S2. Eight guidewires showed cortical contacts, resulting in a total of 2% mismatched screws with subsequent wall violation. The fracture gaps were reduced from 3.6 ± 0.53 mm to 1.2 ± 0.54 mm. During follow-up 3 cases of minor iatrogenic sacral impaction (<5 mm) due to the bolting and 2 cases of screw loosening were observed. Interventional time was 84.0 min with a mean of 2.63 screws per patient whilst acquiring a mean of 93.7 interventional CT-images (DLP 336.7 mGy cm). Conclusions: The treatment of posterior pelvic instability with a guidewire-based screw insertion technique under CT-imaging results in a very high accuracy and efficacy with a low complication rate. Careful attention should be drawn to radiation levels.

  16. Time domain models for damping-controlled fluidelastic instability forces in multi-span tubes with loose supports

    International Nuclear Information System (INIS)

    Hassan, M.A.; Rogers, R.J.; Gerber, A.G.

    2009-01-01

    This paper presents simulations of a loosely supported multi-span tube subjected to turbulence and fluidelastic instability forces. Several time-domain fluid force models simulating the damping controlled fluidelastic instability mechanism in tube arrays have been presented. These models include the negative damping model based on the Connors equation, fluid force coefficient-based models (Chen and Tanaka and Takahara), and two semi-analytical models (Price and Paidoussis; and Lever and Weaver) were implemented in an in-house finite code. Time domain modeling challenges for each of these theories were discussed. The implemented models were validated against available experimental data. The linear simulations showed that the Connors-equation based model exhibits the most conservative prediction of the critical flow velocity when the recommended design values for the Connors equation were used. The models were then utilized to simulate the nonlinear response of a three-span cantilever tube in a square lattice bar support subjected to air crossflow. The tube was subjected to a single-phase flow passing over one of the tube's spans. For each of these models the flow velocity and the support clearance were varied. Special attention was paid to the tube/support interaction parameters that affect wear, such as impact forces, contact ratio, and normal work rate. As the prediction of the linear threshold varies depending on the utilized model, the nonlinear response also differs. The investigated models exhibit similar response characteristics for the impact force, tip lift response, and work rate. Simulation results show that the Connors-based model underestimates the response and the tube/support interaction parameters for the loose support case. (author)

  17. A reduced energy supply strategy in active vibration control

    Science.gov (United States)

    Ichchou, M. N.; Loukil, T.; Bareille, O.; Chamberland, G.; Qiu, J.

    2011-12-01

    In this paper, a control strategy is presented and numerically tested. This strategy aims to achieve the potential performance of fully active systems with a reduced energy supply. These energy needs are expected to be comparable to the power demands of semi-active systems, while system performance is intended to be comparable to that of a fully active configuration. The underlying strategy is called 'global semi-active control'. This control approach results from an energy investigation based on management of the optimal control process. Energy management encompasses storage and convenient restitution. The proposed strategy monitors a given active law without any external energy supply by considering purely dissipative and energy-demanding phases. Such a control law is offered here along with an analysis of its properties. A suboptimal form, well adapted for practical implementation steps, is also given. Moreover, a number of numerical experiments are proposed in order to validate test findings.

  18. A reduced energy supply strategy in active vibration control

    International Nuclear Information System (INIS)

    Ichchou, M N; Loukil, T; Bareille, O; Chamberland, G; Qiu, J

    2011-01-01

    In this paper, a control strategy is presented and numerically tested. This strategy aims to achieve the potential performance of fully active systems with a reduced energy supply. These energy needs are expected to be comparable to the power demands of semi-active systems, while system performance is intended to be comparable to that of a fully active configuration. The underlying strategy is called 'global semi-active control'. This control approach results from an energy investigation based on management of the optimal control process. Energy management encompasses storage and convenient restitution. The proposed strategy monitors a given active law without any external energy supply by considering purely dissipative and energy-demanding phases. Such a control law is offered here along with an analysis of its properties. A suboptimal form, well adapted for practical implementation steps, is also given. Moreover, a number of numerical experiments are proposed in order to validate test findings

  19. Online Traffic Signal Control for Reducing Vehicle Carbon Dioxide Emissions

    Science.gov (United States)

    Oda, Toshihiko; Otokita, Tohru; Niikura, Satoshi

    In Japan, carbon dioxide (CO2) emissions caused by vehicles have been increasing year by year and it is well known that CO2 causes a serious global warming problem. For urban traffic control systems, there is a great demand for realization of signal control measures as soon as possible due to the urgency of the recent environmental situation. This paper describes a new traffic signal control for reducing vehicle CO2 emissions on an arterial road. First, we develop a model for estimating the emissions using the traffic delay and the number of stops a driver makes. Second, to find the optimal control parameters, we introduce a random search method with rapid convergence suitable for an online traffic control. We conduct experiments in Kawasaki to verify the effectiveness of our method. The experiments show that our approach decreases not only the emissions but also congestion and travel time significantly, compared to the method implemented in the real system.

  20. A new approach of the Star Excursion Balance Test to assess dynamic postural control in people complaining from chronic ankle instability.

    Science.gov (United States)

    Pionnier, Raphaël; Découfour, Nicolas; Barbier, Franck; Popineau, Christophe; Simoneau-Buessinger, Emilie

    2016-03-01

    The purpose of this study was to quantitatively and qualitatively assess dynamic balance with accuracy in individuals with chronic ankle instability (CAI). To this aim, a motion capture system was used while participants performed the Star Excursion Balance Test (SEBT). Reached distances for the 8 points of the star were automatically computed, thereby excluding any dependence to the experimenter. In addition, new relevant variables were also computed, such as absolute time needed to reach each distance, lower limb ranges of motion during unipodal stance, as well as absolute error of pointing. Velocity of the center of pressure and range of variation of ground reaction forces have also been assessed during the unipodal phase of the SEBT thanks to force plates. CAI group exhibited smaller reached distances and greater absolute error of pointing than the control group (p<0.05). Moreover, the ranges of motion of lower limbs joints, the velocity of the center of pressure and the range of variation of the ground reaction forces were all significantly smaller in the CAI group (p<0.05). These reduced quantitative and qualitative performances highlighted a lower dynamic postural control. The limited body movements and accelerations during the unipodal stance in the CAI group could highlight a protective strategy. The present findings could help clinicians to better understand the motor strategies used by CAI patients during dynamic balance and may guide the rehabilitation process. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Will PM control undermine China's efforts to reduce soil acidification?

    International Nuclear Information System (INIS)

    Zhao Yu; Duan Lei; Lei Yu; Xing Jia; Nielsen, Chris P.; Hao Jiming

    2011-01-01

    China's strategies to control acidifying pollutants and particulate matter (PM) may be in conflict for soil acidification abatement. Acidifying pollutant emissions are estimated for 2005 and 2020 with anticipated control policies. PM emissions including base cations (BCs) are evaluated with two scenarios, a base case applying existing policy to 2020, and a control case including anticipated tightened measures. Depositions of sulfur (S), nitrogen (N) and BCs are simulated and their acidification risks are evaluated with critical load (CL). In 2005, the area exceeding CL covered 15.6% of mainland China, with total exceedance of 2.2 Mt S. These values decrease in the base scenario 2020, implying partial recovery from acidification. Under more realistic PM control, the respective estimates are 17.9% and 2.4 Mt S, indicating increased acidification risks due to abatement of acid-neutralizing BCs. China's anthropogenic PM abatement will have potentially stronger chemical implications for acidification than developed countries. - Highlights: → We model the emission and deposition of base cations and acid precursors in China. → Soil acidification in China is analyzed with exceedance of critical load. → China's PM control increases the acidification risk even with reduced SO 2 emission. → The impact of PM for acidification is stronger than that in developed countries. - The control of anthropogenic PM emission in China will increase the risk of soil acidification even with reduced SO 2 emission. Such implication is stronger than that in developed countries.

  2. Tai Chi training reduced coupling between respiration and postural control.

    Science.gov (United States)

    Holmes, Matthew L; Manor, Brad; Hsieh, Wan-hsin; Hu, Kun; Lipsitz, Lewis A; Li, Li

    2016-01-01

    In order to maintain stable upright stance, the postural control system must account for the continuous perturbations to the body's center-of-mass including those caused by spontaneous respiration. Both aging and disease increase "posturo-respiratory synchronization;" which reflects the degree to which respiration affects postural sway fluctuations over time. Tai Chi training emphasizes the coordination of respiration and bodily movements and may therefore optimize the functional interaction between these two systems. The purpose of the project was to examine the effect of Tai Chi training on the interaction between respiration and postural control in older adults. We hypothesized that Tai Chi training would improve the ability of the postural control system to compensate for respiratory perturbations and thus, reduce posturo-respiratory synchronization. Participants were recruited from supportive housing facilities and randomized to a 12-week Tai Chi intervention (n=28; 86 ± 5 yrs) or educational-control program (n=34, 85 ± 6 yrs). Standing postural sway and respiration were simultaneously recorded with a force plate and respiratory belt under eyes-open and eyes-closed conditions. Posturo-respiratory synchronization was determined by quantifying the variation of the phase relationship between the dominant oscillatory mode of respiration and corresponding oscillations within postural sway. Groups were similar in age, gender distribution, height, body mass, and intervention compliance. Neither intervention altered average sway speed, sway magnitude or respiratory rate. As compared to the education-control group, however, Tai Chi training reduced posturo-respiratory synchronization when standing with eyes open or closed (ppostural control or respiration, yet reduced the coupling between respiration and postural control. The beneficial effects of Tai Chi training may therefore stem in part from optimization of this multi-system interaction. Copyright © 2015

  3. MODELING CONTROLLED ASYNCHRONOUS ELECTRIC DRIVES WITH MATCHING REDUCERS AND TRANSFORMERS

    Directory of Open Access Journals (Sweden)

    V. S. Petrushin

    2015-04-01

    Full Text Available Purpose. Working out of mathematical models of the speed-controlled induction electric drives ensuring joint consideration of transformers, motors and loadings, and also matching reducers and transformers, both in static, and in dynamic regimes for the analysis of their operating characteristics. Methodology. At mathematical modelling are considered functional, mass, dimensional and cost indexes of reducers and transformers that allows observing engineering and economic aspects of speed-controlled induction electric drives. The mathematical models used for examination of the transitive electromagnetic and electromechanical processes, are grounded on systems of nonlinear differential equations with nonlinear coefficients (parameters of equivalent circuits of motors, varying in each operating point, including owing to appearances of saturation of magnetic system and current displacement in a winding of a rotor of an induction motor. For the purpose of raise of level of adequacy of models a magnetic circuit iron, additional and mechanical losses are considered. Results. Modelling of the several speed-controlled induction electric drives, different by components, but working on a loading equal on character, magnitude and a demanded control range is executed. At use of characteristic families including mechanical, at various parameters of regulating on which performances of the load mechanism are superimposed, the adjusting characteristics representing dependences of a modification of electrical, energy and thermal magnitudes from an angular speed of motors are gained. Originality. The offered complex models of speed-controlled induction electric drives with matching reducers and transformers, give the chance to realize well-founded sampling of components of drives. They also can be used as the design models by working out of speed-controlled induction motors. Practical value. Operating characteristics of various speed-controlled induction electric

  4. Electrical engineering unit for the reactive power control of the load bus at the voltage instability

    Science.gov (United States)

    Kotenev, A. V.; Kotenev, V. I.; Kochetkov, V. V.; Elkin, D. A.

    2018-01-01

    For the purpose of reactive power control error reduction and decrease of the voltage sags in the electric power system caused by the asynchronous motors started the mathematical model of the load bus was developed. The model was built up of the sub-models of the following elements: a transformer, a transmission line, a synchronous and an asynchronous loads and a capacitor bank load, and represents the automatic reactive power control system taking into account electromagnetic processes of the asynchronous motors started and reactive power changing of the electric power system elements caused by the voltage fluctuation. The active power/time and reactive power/time characteristics based on the recommended procedure of the equivalent electric circuit parameters calculation were obtained. The derived automatic reactive power control system was shown to eliminate the voltage sags in the electric power system caused by the asynchronous motors started.

  5. The Effect of Joint Mobilization on Dynamic Postural Control in Patients With Chronic Ankle Instability: A Critically Appraised Topic.

    Science.gov (United States)

    Kosik, Kyle B; Gribble, Phillip A

    2018-01-01

    Clinical Scenario: Dorsiflexion range of motion is an important factor in the performance of the Star Excursion Balance Test (SEBT). While patients with chronic ankle instability (CAI) commonly experience decreased reach distances on the SEBT, ankle joint mobilization has been suggested to be an effective therapeutic intervention for targeting dorsiflexion range of motion. What is the evidence to support ankle joint mobilization for improving performance on the SEBT in patients with CAI? Summary of Key Findings: The literature was searched for articles examining the effects of ankle joint mobilization on scores of the SEBT. A total of 3 peer-reviewed articles were retrieved, 2 prospective individual cohort studies and 1 randomized controlled trial. Only 2 articles demonstrated favorable results following 6 sessions of ankle joint mobilization. Clinical Bottom Line: Despite the mixed results, the majority of the available evidence suggests that ankle joint mobilization improves dynamic postural control. Strength of Recommendation: In accordance with the Centre of Evidence Based Medicine, the inconsistent results and the limited high-quality studies indicate that there is level C evidence to support the use of ankle joint mobilization to improve performance on the SEBT in patients with CAI.

  6. Identifying postural control and thresholds of instability utilizing a motion-based ATV simulator.

    Science.gov (United States)

    2017-01-01

    Our ATV simulator is currently the only one in existence that allows studies of human subjects engaged in active riding, a process that is necessary for ATV operators to perform in order to maintain vehicle control, in a virtual reality environ...

  7. Steering the dynamics within reduced space through quantum learning control

    International Nuclear Information System (INIS)

    Kim, Young Sik

    2003-01-01

    In quantum dynamics of many-body systems, to identify the Hamiltonian becomes more difficult very rapidly as the number of degrees of freedom increases. In order to simplify the dynamics and to deduce dynamically relevant Hamiltonian information, it is desirable to control the dynamics to lie within a reduced space. With a judicious choice for the cost functional, the closed loop optimal control experiments can be manipulated efficiently to steer the dynamics to lie within a subspace of the system eigenstates without requiring any prior detailed knowledge about the system Hamiltonian. The procedure is simulated for optimally controlled population transfer experiments in the system of two degrees of freedom. To show the feasibility of steering the dynamics to lie in a specified subspace, the learning algorithms guiding the dynamics are presented along with frequency filtering. The results demonstrate that the optimal control fields derive the system to the desired target state through the desired subspace

  8. Reducing braking distance by control of semi-active suspension

    Energy Technology Data Exchange (ETDEWEB)

    Niemz, T.

    2007-07-01

    This thesis presents a control algorithm for semi-active suspensions to reduce the braking distance of passenger cars. Active shock absorbers are controlled and used to influence the vertical dynamics during ABS-controlled full braking. The core of the approach presented in this paper is based on a switching control logic. The control algorithm is implemented in a compact class passenger car. Test drives on a real road, using a braking machine for reproducibility reasons, have been executed. It could be shown that it is possible to reduce the braking distance by affecting on the vertical dynamics of a passenger car in general. This is the first experimental result of this kind published ever. The amount of reduction depends on the height profile of the testing track chosen and on the initial velocity. On a road with an unevenness comparable to the one on a typical German Autobahn an average reduction of 1-2%, compared to the best passive damping, was achieved. (orig.)

  9. New solids control system reduced oil on cuttings

    Energy Technology Data Exchange (ETDEWEB)

    Wilkinson, T.P. [Oiltools Europe Ltd., Aberdeen (United Kingdom)

    1996-04-08

    A new solids control system, consisting of four new shakers and a dryer in parallel all discharging into another dryer, significantly reduced the oil on the cuttings in a nine-well offshore drilling program. Cleaned, slurrified cuttings were then discharged overboard. In November 1994, Oiltools (Europe) Ltd. received contracts to upgrade the solids control systems on Sedco Forex`s Sedco 711 and Sovereign Explorer semisubmersible drilling vessels. Sedco Forex required systems that would meet the reduced oil-on-cuttings (OOC) disposal limit of less than 80 g/kg set by the operator, while staying efficient and economical to operate and maintain. In addition, all solids were required to be slurrified for pumping overboard to ensure dispersal away from the subsea center. This article highlights the equipment used and the savings realized on the Sovereign Explorer after the first three wells of a nine-well program.

  10. Controlling Laser Plasma Instabilities Using Temporal Bandwidths Under Shock Ignition Relevant Conditions

    Science.gov (United States)

    Tsung, Frank; Weaver, J.; Lehmberg, R.

    2017-10-01

    We are performing particle-in-cell simulations using the code OSIRIS to study the effects of laser plasma interactions in the presence of temporal bandwidth under plasma conditions relevant to experiments on the Nike laser with induced spatial incoherence (ISI). With ISI, the instantaneous laser intensity can be 3-4 times larger than the average intensity, leading to the excitation of additional TPD modes and producing electrons with larger angular spread. In our simulations, we observe that although ISI can increase the interaction regions for short bursts of time, time-averaged (over many pico-seconds) laser plasma interactions can be reduced by a factor of 2 in systems with sufficiently large bandwidths (where the inverse bandwidth is comparable with the linear growth time). We will quantify these effects and investigate higher dimensional effects such as laser speckles and the effects of Coulomb collisions. Work supported by NRL, NNSA, and NSF.

  11. Sparsity enabled cluster reduced-order models for control

    Science.gov (United States)

    Kaiser, Eurika; Morzyński, Marek; Daviller, Guillaume; Kutz, J. Nathan; Brunton, Bingni W.; Brunton, Steven L.

    2018-01-01

    Characterizing and controlling nonlinear, multi-scale phenomena are central goals in science and engineering. Cluster-based reduced-order modeling (CROM) was introduced to exploit the underlying low-dimensional dynamics of complex systems. CROM builds a data-driven discretization of the Perron-Frobenius operator, resulting in a probabilistic model for ensembles of trajectories. A key advantage of CROM is that it embeds nonlinear dynamics in a linear framework, which enables the application of standard linear techniques to the nonlinear system. CROM is typically computed on high-dimensional data; however, access to and computations on this full-state data limit the online implementation of CROM for prediction and control. Here, we address this key challenge by identifying a small subset of critical measurements to learn an efficient CROM, referred to as sparsity-enabled CROM. In particular, we leverage compressive measurements to faithfully embed the cluster geometry and preserve the probabilistic dynamics. Further, we show how to identify fewer optimized sensor locations tailored to a specific problem that outperform random measurements. Both of these sparsity-enabled sensing strategies significantly reduce the burden of data acquisition and processing for low-latency in-time estimation and control. We illustrate this unsupervised learning approach on three different high-dimensional nonlinear dynamical systems from fluids with increasing complexity, with one application in flow control. Sparsity-enabled CROM is a critical facilitator for real-time implementation on high-dimensional systems where full-state information may be inaccessible.

  12. Fingerprints of dynamical instabilities

    International Nuclear Information System (INIS)

    Chomaz, Ph.; Colonna, M.; Guarnera, A.

    1993-01-01

    It is explained why any reduced descriptions, such as mean field approximation, are stochastic in nature. It is shown that the introduction of this stochastic dynamics leads to a predictive theory in a statistical sens whatever the individual trajectories are characterized by the occurrence of bifurcations, instabilities or phase transitions. Concerning nuclear matter, the spinodal instability is discussed. In such a critical situation, the possibility to replace the stochastic part of the collision integral in the Boltzmann-Langevin model by the numerical noise associated with the finite number of test particles in ordinary BUU treatment is studied. It is shown that the fingerprints of these instabilities are kept during the evolution because of the relatively long recombination time compared with the typical time scales imposed by the Coulomb repulsion and the possible collective expansion. (author) 5 refs., 12 figs

  13. Controlled cooling of an electronic system for reduced energy consumption

    Science.gov (United States)

    David, Milnes P.; Iyengar, Madhusudan K.; Schmidt, Roger R.

    2016-08-09

    Energy efficient control of a cooling system cooling an electronic system is provided. The control includes automatically determining at least one adjusted control setting for at least one adjustable cooling component of a cooling system cooling the electronic system. The automatically determining is based, at least in part, on power being consumed by the cooling system and temperature of a heat sink to which heat extracted by the cooling system is rejected. The automatically determining operates to reduce power consumption of the cooling system and/or the electronic system while ensuring that at least one targeted temperature associated with the cooling system or the electronic system is within a desired range. The automatically determining may be based, at least in part, on one or more experimentally obtained models relating the targeted temperature and power consumption of the one or more adjustable cooling components of the cooling system.

  14. Controlled cooling of an electronic system for reduced energy consumption

    Energy Technology Data Exchange (ETDEWEB)

    David, Milnes P.; Iyengar, Madhusudan K.; Schmidt, Roger R.

    2018-01-30

    Energy efficient control of a cooling system cooling an electronic system is provided. The control includes automatically determining at least one adjusted control setting for at least one adjustable cooling component of a cooling system cooling the electronic system. The automatically determining is based, at least in part, on power being consumed by the cooling system and temperature of a heat sink to which heat extracted by the cooling system is rejected. The automatically determining operates to reduce power consumption of the cooling system and/or the electronic system while ensuring that at least one targeted temperature associated with the cooling system or the electronic system is within a desired range. The automatically determining may be based, at least in part, on one or more experimentally obtained models relating the targeted temperature and power consumption of the one or more adjustable cooling components of the cooling system.

  15. Mitigation of radiation-pressure-induced angular instability of a Fabry–Perot cavity consisting of suspended mirrors

    Energy Technology Data Exchange (ETDEWEB)

    Nagano, Koji, E-mail: knagano@icrr.u-tokyo.ac.jp [KAGRA Observatory, Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwa-no-Ha, Kashiwa, Chiba 277-8582 (Japan); Enomoto, Yutaro; Nakano, Masayuki [KAGRA Observatory, Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwa-no-Ha, Kashiwa, Chiba 277-8582 (Japan); Furusawa, Akira [Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Kawamura, Seiji [KAGRA Observatory, Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwa-no-Ha, Kashiwa, Chiba 277-8582 (Japan)

    2016-12-01

    To observe radiation pressure noise in optical cavities consisting of suspended mirrors, high laser power is necessary. However, because the radiation pressure on the mirrors could cause an angular anti-spring effect, the high laser power could induce angular instability to the cavity. An angular control system using radiation pressure as an actuator, which was previously invented to reduce the anti-spring effect for the low power case, was applied to the higher power case where the angular instability would occur. As a result the angular instability was mitigated. It was also demonstrated that the cavity was unstable without this control system. - Highlights: • High laser power could cause angular instability to a suspended Fabry–Perot cavity. • To mitigate the instability, the control system using radiation pressure is applied. • Mitigating the radiation-pressure-induced angular instability is demonstrated. • It is also confirmed that the cavity would be unstable without the control system.

  16. Control concepts for vehicle drive line to reduce fuel consumption

    Energy Technology Data Exchange (ETDEWEB)

    Ossyra, J.C.

    2005-07-01

    In this work advanced drive line control concepts for off-road vehicles have been developed and investigated to reduce the power losses and finally the fuel consumption of the entire drive system by use of on-line optimization procedure. Two separate closed loop speed controls have been developed for the use on a microcontroller onboard the vehicle: one to control the hydrostatic transmission and the other to control the engine speed. Considering the loss characteristics of the displacement machines in the hydrostatic transmission and the steady state characteristics of the combustion engine by use of pure mathematical approximations of measured curves, a direct optimization strategy is used, which works on-line on a microcontroller. A laboratory hardware-in-the loop test rig has been used to investigate the proposed control concepts. For different typical and desired work cycles of an off-road machine on level ground and uphill a slope the effectiveness of the proposed control concepts have been proven. (orig.)

  17. Long-wave analysis and control of the viscous Rayleigh-Taylor instability with electric fields

    Science.gov (United States)

    Cimpeanu, Radu; Anderson, Thomas; Petropoulos, Peter; Papageorgiou, Demetrios

    2016-11-01

    We investigate the electrostatic stabilization of a viscous thin film wetting the underside of a solid surface in the presence of a horizontally acting electric field. The competition between gravity, surface tension and the nonlocal effect of the applied electric field is captured analytically in the form of a nonlinear evolution equation. A semi-spectral solution strategy is employed to resolve the dynamics of the resulting partial differential equation. Furthermore, we conduct direct numerical simulations (DNS) of the Navier-Stokes equations and assess the accuracy of the obtained solutions when varying the electric field strength from zero up to the point when complete stabilization at the target finite wavelengths occurs. We employ DNS to examine the limitations of the asymptotically derived behavior in the context of increasing liquid film heights, with agreement found to be excellent even beyond the target lengthscales. Regimes in which the thin film assumption is no longer valid and droplet pinch-off occurs are then analyzed. Finally, the asymptotic and computational approaches are used in conjunction to identify efficient active control mechanisms allowing the manipulation of the fluid interface in light of engineering applications at small scales, such as mixing.

  18. Changes in Postural Control After a Ball-Kicking Balance Exercise in Individuals With Chronic Ankle Instability

    Science.gov (United States)

    Conceição, Josilene Souza; Schaefer de Araújo, Felipe Gustavo; Santos, Gilmar Moraes; Keighley, John

    2016-01-01

    Context:  Rehabilitation programs for patients with chronic ankle instability (CAI) generally involve balance-perturbation training (BPT). Anticipatory postural adjustments (APAs) and compensatory postural adjustments (CPAs) are the primary strategies used to maintain equilibrium during body perturbations. Little is known, however, about how APAs and CPAs are modified to promote better postural control for individuals with CAI after BPT. Objective:  To investigate the effect of BPT that involves kicking a ball on postural-control strategies in individuals with CAI. Design:  Randomized controlled clinical trial. Setting:  Laboratory. Patients or Other Participants:  We randomly assigned 44 volunteers with CAI to either a training group (TG; 11 women, 11 men; age = 24 ± 4 years, height = 173.0 ± 9.8 cm, mass = 72.64 ± 11.98 kg) or control group (CG; 11 women, 11 men; age = 22 ± 3 years, height = 171.0 ± 9.7 cm, mass = 70.00 ± 11.03 kg). Intervention(s):  The TG performed a single 30-minute training session that involved kicking a ball while standing on 1 foot. The CG received no intervention. Main Outcome Measure(s):  The primary outcome was the sum of the integrated electromyographic activity (∑∫EMG) of the lower extremity muscles in the supporting limb that were calculated during typical intervals for APAs and CPAs. A secondary outcome was center-of-pressure displacement during similar intervals. Results:  In the TG after training, the ∑∫EMG decreased in both dorsal and ventral muscles during compensatory adjustment (ie, the time interval that followed lower limb movement). During this interval, muscle activity (∑∫EMG) was less in the TG than in the CG. Consequently, center-of-pressure displacement increased during the task after training. Conclusions:  A single session of ball-kicking BPT promoted changes in postural-control strategies in individuals with CAI. These results should stimulate new and more comprehensive studies to

  19. Predicting Catastrophic BGP Routing Instabilities

    National Research Council Canada - National Science Library

    Nguyen, Lien

    2004-01-01

    .... Currently, this critical function is performed by the Border Gateway Protocol (BGP) version 4 RF01771. Like all routing protocols, BGP is vulnerable to instabilities that reduce its effectiveness...

  20. Plasma physics and instabilities

    International Nuclear Information System (INIS)

    Lashmore-Davies, C.N.

    1981-01-01

    These lectures procide an introduction to the theory of plasmas and their instabilities. Starting from the Bogoliubov, Born, Green, Kirkwood, and Yvon (BBGKY) hierarchy of kinetic equations, the additional concept of self-consistent fields leads to the fundamental Vlasov equation and hence to the warm two-fluid model and the one-fluid MHD, or cold, model. The properties of small-amplitude waves in magnetized (and unmagnetized) plasmas, and the instabilities to which they give rise, are described in some detail, and a complete chapter is devoted to Landau damping. The linear theory of plasma instabilities is illustrated by the current-driven electrostatic kind, with descriptions of the Penrose criterion and the energy principle of ideal MHD. There is a brief account of the application of feedback control. The non-linear theory is represented by three examples: quasi-linear velocity-space instabilities, three-wave instabilities, and the stability of an arbitrarily largeamplitude wave in a plasma. (orig.)

  1. Nonlinear behavior of the radiative condensation instability

    International Nuclear Information System (INIS)

    McCarthy, D.; Drake, J.F.

    1991-01-01

    An investigation of the nonlinear behavior of the radiative condensation instability is presented in a simple one-dimensional magnetized plasma. It is shown that the radiative condensation is typically a nonlinear instability---the growth of the instability is stronger once the disturbance reaches finite amplitude. Moreover, classical parallel thermal conduction is insufficient by itself to saturate the instability. Radiative collapse continues until the temperature in the high density condensation falls sufficiently to reduce the radiation rate

  2. Control-oriented reduced order modeling of dipteran flapping flight

    Science.gov (United States)

    Faruque, Imraan

    Flying insects achieve flight stabilization and control in a manner that requires only small, specialized neural structures to perform the essential components of sensing and feedback, achieving unparalleled levels of robust aerobatic flight on limited computational resources. An engineering mechanism to replicate these control strategies could provide a dramatic increase in the mobility of small scale aerial robotics, but a formal investigation has not yet yielded tools that both quantitatively and intuitively explain flapping wing flight as an "input-output" relationship. This work uses experimental and simulated measurements of insect flight to create reduced order flight dynamics models. The framework presented here creates models that are relevant for the study of control properties. The work begins with automated measurement of insect wing motions in free flight, which are then used to calculate flight forces via an empirically-derived aerodynamics model. When paired with rigid body dynamics and experimentally measured state feedback, both the bare airframe and closed loop systems may be analyzed using frequency domain system identification. Flight dynamics models describing maneuvering about hover and cruise conditions are presented for example fruit flies (Drosophila melanogaster) and blowflies (Calliphorids). The results show that biologically measured feedback paths are appropriate for flight stabilization and sexual dimorphism is only a minor factor in flight dynamics. A method of ranking kinematic control inputs to maximize maneuverability is also presented, showing that the volume of reachable configurations in state space can be dramatically increased due to appropriate choice of kinematic inputs.

  3. Startle stimuli reduce the internal model control in discrete movements.

    Science.gov (United States)

    Wright, Zachary A; Rogers, Mark W; MacKinnon, Colum D; Patton, James L

    2009-01-01

    A well known and major component of movement control is the feedforward component, also known as the internal model. This model predicts and compensates for expected forces seen during a movement, based on recent experience, so that a well-learned task such as reaching to a target can be executed in a smooth straight manner. It has recently been shown that the state of preparation of planned movements can be tested using a startling acoustic stimulus (SAS). SAS, presented 500, 250 or 0 ms before the expected "go" cue resulted in the early release of the movement trajectory associated with the after-effects of the force field training (i.e. the internal model). In a typical motor adaptation experiment with a robot-applied force field, we tested if a SAS stimulus influences the size of after-effects that are typically seen. We found that in all subjects the after-effect magnitudes were significantly reduced when movements were released by SAS, although this effect was not further modulated by the timing of SAS. Reduced after-effects reveal at least partial existence of learned preparatory control, and identify startle effects that could influence performance in tasks such as piloting, teleoperation, and sports.

  4. Empirical Reduced-Order Modeling for Boundary Feedback Flow Control

    Directory of Open Access Journals (Sweden)

    Seddik M. Djouadi

    2008-01-01

    Full Text Available This paper deals with the practical and theoretical implications of model reduction for aerodynamic flow-based control problems. Various aspects of model reduction are discussed that apply to partial differential equation- (PDE- based models in general. Specifically, the proper orthogonal decomposition (POD of a high dimension system as well as frequency domain identification methods are discussed for initial model construction. Projections on the POD basis give a nonlinear Galerkin model. Then, a model reduction method based on empirical balanced truncation is developed and applied to the Galerkin model. The rationale for doing so is that linear subspace approximations to exact submanifolds associated with nonlinear controllability and observability require only standard matrix manipulations utilizing simulation/experimental data. The proposed method uses a chirp signal as input to produce the output in the eigensystem realization algorithm (ERA. This method estimates the system's Markov parameters that accurately reproduce the output. Balanced truncation is used to show that model reduction is still effective on ERA produced approximated systems. The method is applied to a prototype convective flow on obstacle geometry. An H∞ feedback flow controller is designed based on the reduced model to achieve tracking and then applied to the full-order model with excellent performance.

  5. Reduced phase error through optimized control of a superconducting qubit

    International Nuclear Information System (INIS)

    Lucero, Erik; Kelly, Julian; Bialczak, Radoslaw C.; Lenander, Mike; Mariantoni, Matteo; Neeley, Matthew; O'Connell, A. D.; Sank, Daniel; Wang, H.; Weides, Martin; Wenner, James; Cleland, A. N.; Martinis, John M.; Yamamoto, Tsuyoshi

    2010-01-01

    Minimizing phase and other errors in experimental quantum gates allows higher fidelity quantum processing. To quantify and correct for phase errors, in particular, we have developed an experimental metrology - amplified phase error (APE) pulses - that amplifies and helps identify phase errors in general multilevel qubit architectures. In order to correct for both phase and amplitude errors specific to virtual transitions and leakage outside of the qubit manifold, we implement 'half derivative', an experimental simplification of derivative reduction by adiabatic gate (DRAG) control theory. The phase errors are lowered by about a factor of five using this method to ∼1.6 deg. per gate, and can be tuned to zero. Leakage outside the qubit manifold, to the qubit |2> state, is also reduced to ∼10 -4 for 20% faster gates.

  6. Selection criteria for patients with chronic ankle instability in controlled research: a position statement of the International Ankle Consortium

    NARCIS (Netherlands)

    Gribble, P.A.; Delahunt, E.; Bleakley, C.M.; Caulfield, B.; Docherty, C.L.; Fong, D.T.; Fourchet, F.; Hertel, J.; Hiller, C.E.; Kaminski, T.W.; McKeon, P.O.; Refshauge, K.M.; Wees, P.J. van der; Vicenzino, W.; Wikstrom, E.A.

    2014-01-01

    While research on chronic ankle instability (CAI) and awareness of its impact on society and health care systems has grown substantially in the last 2 decades, the inconsistency in participant or patient selection criteria across studies presents a potential obstacle to addressing the problem

  7. Selection criteria for patients with chronic ankle instability in controlled research: a position statement of the International Ankle Consortium

    NARCIS (Netherlands)

    Gribble, P.A.; Delahunt, E.; Bleakley, C.; Caulfield, B.; Docherty, C.; Fourchet, F.; Fong, D.T.; Hertel, J.; Hiller, C.; Kaminski, T.; McKeon, P.; Refshauge, K.; Wees, P.J. van der; Vincenzino, B.; Wikstrom, E.

    2014-01-01

    While research on chronic ankle instability (CAI) and awareness of its impact on society and health care systems has grown substantially in the last 2 decades, the inconsistency in participant/patient selection criteria across studies presents a potential obstacle to addressing the problem properly.

  8. Manipulation and control of instabilities for surfactant-laden liquid film flowing down an inclined plane using a deformable solid layer

    Science.gov (United States)

    Tomar, Dharmendra S.; Sharma, Gaurav

    2018-01-01

    that for cases when the stabilizing contribution of surfactant is not sufficient for suppressing GL mode instability, a deformable solid coating could be employed to suppress free surface instability without triggering Marangoni or liquid-solid interfacial modes. Specifically, we have shown that for a given solid thickness, as the shear modulus of the solid layer decreases (i.e., the solid becomes more deformable) the GL mode instability is suppressed. With further decrease in shear modulus, the Marangoni and liquid-solid interfacial modes become unstable. Thus, there exists a stability window in terms of shear modulus where the surfactant-laden film flow remains stable even when the Marangoni number is below the critical value required for free surface instability suppression. Further, when the Marangoni number is greater than the critical value so that the GL mode remains stable in the rigid limit or with the deformable wall, the increase in wall deformability or solid thickness triggers Marangoni mode instability and, thus, renders a stable flow configuration into an unstable one. Thus, we show that the soft solid layer can be used to manipulate and control the stability of surfactant-laden film flows.

  9. Gravitational Instabilities in Circumstellar Disks

    Science.gov (United States)

    Kratter, Kaitlin; Lodato, Giuseppe

    2016-09-01

    Star and planet formation are the complex outcomes of gravitational collapse and angular momentum transport mediated by protostellar and protoplanetary disks. In this review, we focus on the role of gravitational instability in this process. We begin with a brief overview of the observational evidence for massive disks that might be subject to gravitational instability and then highlight the diverse ways in which the instability manifests itself in protostellar and protoplanetary disks: the generation of spiral arms, small-scale turbulence-like density fluctuations, and fragmentation of the disk itself. We present the analytic theory that describes the linear growth phase of the instability supplemented with a survey of numerical simulations that aim to capture the nonlinear evolution. We emphasize the role of thermodynamics and large-scale infall in controlling the outcome of the instability. Despite apparent controversies in the literature, we show a remarkable level of agreement between analytic predictions and numerical results. In the next part of our review, we focus on the astrophysical consequences of the instability. We show that the disks most likely to be gravitationally unstable are young and relatively massive compared with their host star, Md/M*≥0.1. They will develop quasi-stable spiral arms that process infall from the background cloud. Although instability is less likely at later times, once infall becomes less important, the manifestations of the instability are more varied. In this regime, the disk thermodynamics, often regulated by stellar irradiation, dictates the development and evolution of the instability. In some cases the instability may lead to fragmentation into bound companions. These companions are more likely to be brown dwarfs or stars than planetary mass objects. Finally, we highlight open questions related to the development of a turbulent cascade in thin disks and the role of mode-mode coupling in setting the maximum angular

  10. Taming Instabilities in Plasma Discharges

    International Nuclear Information System (INIS)

    Klinger, T.; Krahnstover, N. O.; Mausbach, T.; Piel, A.

    2000-01-01

    Recent experimental work on taming instabilities in plasma discharges is discussed. Instead of suppressing instabilities, it is desired to achieve control over their dynamics, done by perturbing appropriately the current flow in the external circuit of the discharge. Different discrete and continuous feedback as well as open-loop control schemes are applied. Chaotic oscillations in plasma diodes are controlled using the OGY discrete feedback scheme. This is demonstrated both in experiment and computer simulation. Weakly developed ionization wave turbulence is tamed by continuous feedback control. Open-loop control of stochastic fluctuations - stochastic resonance - is demonstrated in a thermionic plasma diode. (author)

  11. Surgical treatment of chest instability

    International Nuclear Information System (INIS)

    Kitka, M.; Masek, M.

    2015-01-01

    Fractures of the ribs is the most common thoracic injury after blunt trauma. Chest wall instability (flail chest) is a common occurrence in the presence of multiple ribs fracture. Unilateral or bilateral fractures more ribs anteriorly or posteriorly will produce enough instability that paradoxical respiratory motion results in hypoventilation of an unacceptable degree. Open approach and surgical stabilisation of the chest preserved pulmonary function, improved pain control, minimized posttraumatic deformities and shorter back to work time. (author)

  12. Stability and dewetting of metal nanoparticle filled thin polymer films: control of instability length scale and dynamics.

    Science.gov (United States)

    Mukherjee, Rabibrata; Das, Soma; Das, Anindya; Sharma, Satinder K; Raychaudhuri, Arup K; Sharma, Ashutosh

    2010-07-27

    We investigate the influence of gold nanoparticle addition on the stability, dewetting, and pattern formation in ultrathin polymer-nanoparticle (NP) composite films by examining the length and time scales of instability, morphology, and dynamics of dewetting. For these 10-50 nm thick (h) polystyrene (PS) thin films containing uncapped gold nanoparticles (diameter approximately 3-4 nm), transitions from complete dewetting to arrested dewetting to absolute stability were observed depending on the concentration of the particles. Experiments show the existence of three distinct stability regimes: regime 1, complete dewetting leading to droplet formation for nanoparticle concentration of 2% (w/w) or below; regime 2, partial dewetting leading to formation of arrested holes for NP concentrations in the range of 3-6%; and regime 3, complete inhibition of dewetting for NP concentrations of 7% and above. Major results are (a) length scale of instability, where lambdaH approximately hn remains unchanged with NP concentration in regime 1 (n approximately 2) but increases in regime 2 with a change in the scaling relation (n approximately 3-3.5); (b) dynamics of instability and dewetting becomes progressively sluggish with an increase in the NP concentration; (c) there are distinct regimes of dewetting velocity at low NP concentrations; (d) force modulation AFM, as well as micro-Raman analysis, shows phase separation and aggregation of the gold nanoparticles within each dewetted polymer droplet leading to the formation of a metal core-polymer shell morphology. The polymer shell could be removed by washing in a selective solvent, thus exposing an array of bare gold nanoparticle aggregates.

  13. The Effect of Fatigue and Instability on Postural Control Parameters in Standing Posture in Healthy Adults and Patients with Chronic Low Back Pain

    Directory of Open Access Journals (Sweden)

    Amir Hosein Kahlaee

    2012-06-01

    Full Text Available Background: This study aims at analyzing the effect of fatigue and instability on postural control parameters in both healthy people and patients with the chronic nonspecific low-back pain.Materials and Methods: In this non-experimental case-control study, oscillations of center of pressure were statistically analyzed in 16 healthy people and 15 patients with the chronic nonspecific low back pain. The analysis was conducted through two stages: before and after fatigue and under both stable and unstable surfaces. Results: Under the pre-fatigue, stable condition, there was not any difference between the two groups. Both fatigue and unstable surface changed our variables (sway area, range, velocity, frequency and total power of the signal. All the changes in variables were significant in the low-back pain group; while changes in the healthy group only covered the time-domain variables. The effect of instability was higher than that of fatigue. Conclusion: The postural control system for patients with low-back pain before fatigue and under stable condition, revealed sufficient competence to provide postural stability and its function cannot be differentiated from that in healthy people. Meanwhile, different mechanisms were used by these patients to confront stability challenging factors and further neural activity was required to counteract such factors.

  14. An analysis of instabilities of nuclear-coupled density-wave in BWR using modern frequency-domain control theory

    International Nuclear Information System (INIS)

    Zhao Yangping; Gao Huahun; Fu Longzhou

    1991-01-01

    A state-of-the-art multi-variable frequency-domain model has been developed for analysis of instabilities of nuclear-coupled density-wave in BWR core. The characteristic locus method is used for analysing the stability of BWR. A computer code-NUCTHIA has been derived. The model has been tested against the existing experimental data and compared with results of past single-variable analyses. By using the NUCTHIA code, the investigations of effects of main system parameters on BWW core stability have also been made. All the results are consistent with the experimental data

  15. REDUCING THE THREAT TO CONTROL INVASIVE SIGNAL CRAYFISH REDUCING: THE POTENTIAL USE OF PHEROMONES

    Directory of Open Access Journals (Sweden)

    STEBBING P. D.

    2003-04-01

    Full Text Available The need for an effective method of controlling invasive species of crayfish is of utmost importance given the plight of Europe’s native crayfish species. Many techniques have been applied to the growing problem with little success. Pheromones have been used to control terrestrial insect pests for a number of years with many success stories. The concept of applying pheromone control methods to the aquatic environment is by no means new, but has not been previously developed. This paper discusses the preliminary results from field trials testing traps baited with Pacifastacus leniusculus pheromones, and the potential application of the pheromones in controlling P. leniusculus populations.

  16. System Detects Vibrational Instabilities

    Science.gov (United States)

    Bozeman, Richard J., Jr.

    1990-01-01

    Sustained vibrations at two critical frequencies trigger diagnostic response or shutdown. Vibration-analyzing electronic system detects instabilities of combustion in rocket engine. Controls pulse-mode firing of engine and identifies vibrations above threshold amplitude at 5.9 and/or 12kHz. Adapted to other detection and/or control schemes involving simultaneous real-time detection of signals above or below preset amplitudes at two or more specified frequencies. Potential applications include rotating machinery and encoders and decoders in security systems.

  17. Knee motion variability in patients with knee osteoarthritis: the effect of self-reported instability

    Science.gov (United States)

    Gustafson, Jonathan A.; Robinson, Megan E.; Fitzgerald, G. Kelley; Tashman, Scott; Farrokhi, Shawn

    2015-01-01

    Background Knee osteoarthritis has been previously associated with a stereotypical knee-stiffening gait pattern and reduced knee joint motion variability due to increased antagonist muscle co-contractions and smaller utilized arc of motion during gait. However, episodic self-reported instability may be a sign of excessive motion variability for a large subgroup of patients with knee osteoarthritis. The objective of this work was to evaluate the differences in knee joint motion variability during gait in patients with knee osteoarthritis with and without self-reported instability compared to a control group of older adults with asymptomatic knees. Methods Forty-three subjects, 8 with knee osteoarthritis but no reports of instability (stable), 11 with knee osteoarthritis and self-reported instability (unstable), and 24 without knee osteoarthritis or instability (control) underwent Dynamic Stereo X-ray analysis during a decline gait task on a treadmill. Knee motion variability was assessed using parametric phase plots during the loading response phase of decline gait. Findings The stable group demonstrated decreased sagittal-plane motion variability compared to the control group (p=0.04), while the unstable group demonstrated increased sagittal-plane motion variability compared to the control (p=0.003) and stable groups (pknee motion variability in patients with knee osteoarthritis without self-reported instability supports previous research. However, presence of self-reported instability is associated with increased knee motion variability in patients with knee osteoarthritis and warrants further investigation. PMID:25796536

  18. Control of Modular Multilevel Converter with reduced internal data exchange

    DEFF Research Database (Denmark)

    Máthé, Lászlo; Burlacu, Paul Dan; Teodorescu, Remus

    2017-01-01

    for such an application, several key parameters have to be considered such as high speed data transfer with low propagation delay, data integrity, and ability for accurate synchronization. In order to minimize the data flow in the MMC a hierarchical control is proposed where a CCU calculates an identical reference......Modular Multilevel Converters (MMC) are penetrating due to their superior performances. Due to the modular structure of the converter, communication platform has to be established between the Sub-Modules (SM) and a Central Controller Unit (CCU). When the communication platform is designed...... for all the SMs while the modulation and capacitor voltage balancing is performed in the controller from the SM. Thus, at each sampling instance only four bytes references are sent by the central controller to the controllers from the SM, while one or two bytes are received from SMs. Further, the control...

  19. Linear Parameter Varying Versus Linear Time Invariant Reduced Order Controller Design of Turboprop Aircraft Dynamics

    Directory of Open Access Journals (Sweden)

    Widowati

    2012-07-01

    Full Text Available The applicability of parameter varying reduced order controllers to aircraft model is proposed. The generalization of the balanced singular perturbation method of linear time invariant (LTI system is used to reduce the order of linear parameter varying (LPV system. Based on the reduced order model the low-order LPV controller is designed by using synthesis technique. The performance of the reduced order controller is examined by applying it to lateral-directional control of aircraft model having 20th order. Furthermore, the time responses of the closed loop system with reduced order LPV controllers and reduced order LTI controller is compared. From the simulation results, the 8th order LPV controller can maintain stability and to provide the same level of closed-loop systems performance as the full-order LPV controller. It is different with the reduced-order LTI controller that cannot maintain stability and performance for all allowable parameter trajectories.

  20. Analyses of MHD instabilities

    International Nuclear Information System (INIS)

    Takeda, Tatsuoki

    1985-01-01

    In this article analyses of the MHD stabilities which govern the global behavior of a fusion plasma are described from the viewpoint of the numerical computation. First, we describe the high accuracy calculation of the MHD equilibrium and then the analysis of the linear MHD instability. The former is the basis of the stability analysis and the latter is closely related to the limiting beta value which is a very important theoretical issue of the tokamak research. To attain a stable tokamak plasma with good confinement property it is necessary to control or suppress disruptive instabilities. We, next, describe the nonlinear MHD instabilities which relate with the disruption phenomena. Lastly, we describe vectorization of the MHD codes. The above MHD codes for fusion plasma analyses are relatively simple though very time-consuming and parts of the codes which need a lot of CPU time concentrate on a small portion of the codes, moreover, the codes are usually used by the developers of the codes themselves, which make it comparatively easy to attain a high performance ratio on the vector processor. (author)

  1. Does Public Sector Control Reduce Variance in School Quality?

    Science.gov (United States)

    Pritchett, Lant; Viarengo, Martina

    2015-01-01

    Does the government control of school systems facilitate equality in school quality? Whether centralized or localized control produces more equality depends not only on what "could" happen in principle, but also on what does happen in practice. We use the Programme for International Student Assessment (PISA) database to examine the…

  2. Multivariable robust adaptive controller using reduced-order model

    Directory of Open Access Journals (Sweden)

    Wei Wang

    1990-04-01

    Full Text Available In this paper a multivariable robust adaptive controller is presented for a plant with bounded disturbances and unmodeled dynamics due to plant-model order mismatches. The robust stability of the closed-loop system is achieved by using the normalization technique and the least squares parameter estimation scheme with dead zones. The weighting polynomial matrices are incorporated into the control law, so that the open-loop unstable or/and nonminimum phase plants can be handled.

  3. Investigation and control of dc arc jet instabilities to obtain a self-sustained pulsed laminar arc jet

    International Nuclear Information System (INIS)

    Krowka, J; Rat, V; Coudert, J F

    2013-01-01

    The uncontrolled arc plasma instabilities in suspension plasma spraying or solution precursor plasma spraying cause non-homogeneous plasma treatments of material during their flight and also on coatings during their formation. This paper shows that the arc motion in dc plasma torches mainly originates in two main modes of oscillation (Helmholtz and restrike modes). The emphasis is put on the restrike mode in which the time component is extracted after building up and applying a numerical filter to raw arc voltage signals. The dependence of re-arcing events on experimental parameters is analysed in the frame of a phenomenological restrike model. It is shown that when the restrike frequency reaches the Helmholtz one, both modes are locked together and a pulsed arc jet is generated. (paper)

  4. Instability and Transition of Flow at, and Near, an Attachment-line - Including Control by Surface Suction

    Science.gov (United States)

    Smith, A.

    1996-01-01

    Advances in aviation during and following the Second World War led to an enormous improvement in the performance of aircraft. The push for enhanced efficiency brought cruise speeds into the transonic range, where the associated drag rise due to the appearance of shock-waves became a limiting factor. Wing sweep was adopted to delay the onset of this drag rise, but with this development came several new and unforeseen problems. Preliminary theoretical work assumed that the boundary layer transition characteristics of a swept wing would be subject to the independence principle, so the chordwise transition position could be predicted from two-dimensional work Gas turbine development has now reached a point where additional increases in efficiency are both difficult and expensive to achieve. Consequently, aircraft manufacturers are looking elsewhere for ways to reduce Direct Operating Costs (DOC's) or increase military performance. The attention of industry is currently focusing on Hybrid Laminar Flow Control (HLFC) as a possible method of reducing DOC's for civil aircraft. Following this study and discussions with NASA Langley and Boeing a different series of questions have been addressed in the present work. There are five areas of interest: Relaminarisation of the attachment-line boundary layer when the value of R exceeds 600. The effects of large suction levels on transition in the attachment-line boundary layer (ie critical oversuction). The transition characteristics of a relaminarised attachment-line flow which encounters a non-porous surface. The effect of attachment-line suction on the spanwise propagation of gross disturbances emanating from the wing-fuselage junction. The attachment-line transition caused by surface blowing.

  5. Synchronous temperature rate control for refrigeration with reduced energy consumption

    Science.gov (United States)

    Gomes, Alberto Regio; Keres, Stephen L.; Kuehl, Steven J.; Litch, Andrew D.; Richmond, Peter J.; Wu, Guolian

    2015-09-22

    Methods of operation for refrigerator appliance configurations with a controller, a condenser, at least one evaporator, a compressor, and two refrigeration compartments. The configuration may be equipped with a variable-speed or variable-capacity compressor, variable speed evaporator or compartment fans, a damper, and/or a dual-temperature evaporator with a valve system to control flow of refrigerant through one or more pressure reduction devices. The methods may include synchronizing alternating cycles of cooling each compartment to a temperature approximately equal to the compartment set point temperature by operation of the compressor, fans, damper and/or valve system. The methods may also include controlling the cooling rate in one or both compartments. Refrigeration compartment cooling may begin at an interval before or after when the freezer compartment reaches its lower threshold temperature. Freezer compartment cooling may begin at an interval before or after when the freezer compartment reaches its upper threshold temperature.

  6. Synchronous temperature rate control for refrigeration with reduced energy consumption

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Alberto Regio; Keres, Stephen L.; Kuehl, Steven J.; Litch, Andrew D.; Richmond, Peter J.; Wu, Guolian

    2017-11-07

    Methods of operation for refrigerator appliance configurations with a controller, a condenser, at least one evaporator, a compressor, and two refrigeration compartments. The configuration may be equipped with a variable-speed or variable-capacity compressor, variable speed evaporator or compartment fans, a damper, and/or a dual-temperature evaporator with a valve system to control flow of refrigerant through one or more pressure reduction devices. The methods may include synchronizing alternating cycles of cooling each compartment to a temperature approximately equal to the compartment set point temperature by operation of the compressor, fans, damper and/or valve system. The methods may also include controlling the cooling rate in one or both compartments. Refrigeration compartment cooling may begin at an interval before or after when the freezer compartment reaches its lower threshold temperature. Freezer compartment cooling may begin at an interval before or after when the freezer compartment reaches its upper threshold temperature.

  7. Are Tobacco Control Policies Effective in Reducing Young Adult Smoking?

    Science.gov (United States)

    Farrelly, Matthew C.; Loomis, Brett R.; Kuiper, Nicole; Han, Beth; Gfroerer, Joseph; Caraballo, Ralph S.; Pechacek, Terry F.; Couzens, G. Lance

    2015-01-01

    Purpose We examined the influence of tobacco control program funding, smoke-free air laws, and cigarette prices on young adult smoking outcomes. Methods We use a natural experimental design approach that uses the variation in tobacco control policies across states and over time to understand their influence on tobacco outcomes. We combine individual outcome data with annual state-level policy data to conduct multivariable logistic regression models, controlling for an extensive set of sociodemographic factors. The participants are 18- to 25-year-olds from the 2002–2009 National Surveys on Drug Use and Health. The three main outcomes are past-year smoking initiation, and current and established smoking. A current smoker was one who had smoked on at least 1 day in the past 30 days. An established smoker was one who had smoked 1 or more cigarettes in the past 30 days and smoked at least 100 cigarettes in his or her lifetime. Results Higher levels of tobacco control program funding and greater smoke-free-air law coverage were both associated with declines in current and established smoking (p smoke-free air laws was associated with lower past year initiation with marginal significance (p = .058). Higher cigarette prices were not associated with smoking outcomes. Had smoke-free-air law coverage and cumulative tobacco control funding remained at 2002 levels, current and established smoking would have been 5%–7% higher in 2009. Conclusions Smoke-free air laws and state tobacco control programs are effective strategies for curbing young adult smoking. PMID:24268360

  8. Anisotropic gravitational instability

    International Nuclear Information System (INIS)

    Polyachenko, V.L.; Fridman, A.M.

    1988-01-01

    Exact solutions of stability problems are obtained for two anisotropic gravitational systems of different geometries - a layer of finite thickness at rest and a rotating cylinder of finite radius. It is shown that the anisotropic gravitational instability which develops in both cases is of Jeans type. However, in contrast to the classical aperiodic Jeans instability, this instability is oscillatory. The physics of the anisotropic gravitational instability is investigated. It is shown that in a gravitating layer this instability is due, in particular, to excitation of previously unknown interchange-Jeans modes. In the cylinder, the oscillatory Jeans instability is associated with excitation of a rotational branch, this also being responsible for the beam gravitational instability. This is the reason why this instability and the anisotropic gravitational instability have so much in common

  9. REDUCING WASTEWATER FROM CUCUMBER PICKLING PROCESS BY CONTROLLED CULTURE FERMENTATION

    Science.gov (United States)

    On a demonstration scale, the controlled culture fermentation process (CCF) developed by the U.S. Food Fermentation Laboratory was compared with the conventional natural fermentation process (NF) in regard to product quality and yield and volume and concentration of wastewaters. ...

  10. Reduce Fraud Risk in Your District with Stronger Internal Controls

    Science.gov (United States)

    Okrzesik, Daryl J.; Nuehring, Bert G.

    2011-01-01

    Internal accounts offer schools a faster, more convenient way to handle the income and expenses that result from student fees, school clubs and organizations, field trips, fund-raising, and similar activities. But this convenience also incurs the added risk of fraud. Fortunately, there are proven ways to strengthen internal controls and reduce…

  11. Delayed chromosomal instability induced by DNA damage

    International Nuclear Information System (INIS)

    Morgan, W.F.; Marder, B.A.; Day, J.P.

    1994-01-01

    Cellular exposure to DNA damaging agents rapidly results in a dose dependent increase in chromosomal breakage and gross structural chromosomal rearrangements. Over recent years, evidence has been accumulating indicating genomic instability can manifest multiple generations after cellular exposure to physical and chemical DNA damaging agents. Genomic instability manifests in the progeny of surviving cells, and has been implicated in mutation, gene application, cellular transformation, and cell killing. To investigate chromosome instability following DNA damage, we have used fluorescence in situ hybridization to detect chromosomal rearrangements in a human/hamster somatic hybrid cell line following exposure to ionizing radiation. Delayed chromosomal instability was detected when multiple populations of uniquely arranged metaphases were observed in clonal isolates raised from single cells surviving X-irradiation many generations after exposure. At higher radiation doses, chromosomal instability was observed in a relatively high frequency of surviving clones and, in general, those clones showed delayed chromosome instability also showed reduced survival as measured by colony forming ability

  12. Reduced hippocampal IL-10 expression, altered monoaminergic activity and anxiety and depressive-like behavior in female mice subjected to chronic social instability stress.

    Science.gov (United States)

    Labaka, Ainitze; Gómez-Lázaro, Eneritz; Vegas, Oscar; Pérez-Tejada, Joana; Arregi, Amaia; Garmendia, Larraitz

    2017-09-29

    Evidence indicates that release of pro-inflammatory cytokines induced by social stress contributes to affective disorders. Additionally, there are known sex differences in both the stress response and the stressors that can elicit this response. In this regard, the chronic social instability (CSI) rodent model of stress appears to be the best fit for the social nature of females. This study analyzed the effects of CSI on female mouse behavior, hippocampal cytokine expression, tryptophan metabolism and monoaminergic activity. The activity of hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-gonadal (HPG) axes were also measured. Results showed a decrease in sucrose consumption in stressed subjects, indicative of anhedonic behavior and an increase in climbing activity in the forced swimming test (FST) and in whisking behavior, which have been associated with anxiety. Decreased interleukin-10 (IL-10) expression was found in the hippocampus of the stressed mice, while no differences in pro-inflammatory cytokine expression and tryptophan (TRYP), kynurenine (KYN) or 3-hydroxy kynurenine (3-HK) levels were found. Increased hippocampal serotoninergic and noradrenergic activity was observed in stressed mice. The higher plasma corticosterone and lower hypothalamic glucocorticoid receptor (GR) expression levels showed an increase in HPA activity after CSI. No differences were found in the plasma estradiol levels or the central estrogen receptors (ERα and ERβ) expression levels. These data indicate that the CSI stress-induced behavioral and physiological changes associated with anxiety and depressive disorders. Although additional studies are warranted, the results suggest an involvement of anti-inflammatory cytokines in the biobehavioral effects of social stress in female mice. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Selection criteria for patients with chronic ankle instability in controlled research: a position statement of the International Ankle Consortium.

    Science.gov (United States)

    Gribble, Phillip A; Delahunt, Eamonn; Bleakley, Chris; Caulfield, Brian; Docherty, Carrie; Fourchet, François; Fong, Daniel Tik-Pui; Hertel, Jay; Hiller, Claire; Kaminski, Thomas; McKeon, Patrick; Refshauge, Kathryn; van der Wees, Philip; Vincenzino, Bill; Wikstrom, Erik

    2014-07-01

    While research on chronic ankle instability (CAI) and awareness of its impact on society and health care systems has grown substantially in the last 2 decades, the inconsistency in participant/patient selection criteria across studies presents a potential obstacle to addressing the problem properly. This major gap within the literature limits the ability to generalise this evidence to the target patient population. Therefore, there is a need to provide standards for patient/participant selection criteria in research focused on CAI with justifications using the best available evidence. The International Ankle Consortium provides this position paper to present and discuss an endorsed set of selection criteria for patients with CAI based on the best available evidence to be used in future research and study designs. These recommendations will enhance the validity of research conducted in this clinical population with the end goal of bringing the research evidence to the clinician and patient. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  14. Cognitive control reduces sensitivity to relational aggression among adolescent girls.

    Science.gov (United States)

    Baird, Abigail A; Silver, Shari H; Veague, Heather B

    2010-01-01

    Relational aggression is a type of aggression that aims to hurt others through relationships and includes behaviors such as gossip and ostracism. This type of aggression is very common among adolescent girls, and in its more intense forms has been linked with poor psychosocial outcomes, including depression and suicide. In the present study we investigated whether individual differences in sensitivity to relational aggression among adolescent girls predicted recruitment of neural networks associated with executive function and cognitive control. Neural response was measured using functional magnetic resonance imaging during an affect recognition task that included unfamiliar peer faces. A finding of relatively fewer reports of being victimized by relational aggression was associated with increased recruitment of bilateral dorsolateral prefrontal cortices as well as anterior and posterior cingulate cortices in response to the affect recognition task, as well as with greater competence on behavioral measures of executive function. Our results suggest that girls who are able to recruit specific frontal networks to improve cognitive and executive control are less sensitive to relational aggression. © 2010 Psychology Press

  15. Ocean acidification reduces the crystallographic control in juvenile mussel shells.

    Science.gov (United States)

    Fitzer, Susan C; Cusack, Maggie; Phoenix, Vernon R; Kamenos, Nicholas A

    2014-10-01

    Global climate change threatens the oceans as anthropogenic carbon dioxide causes ocean acidification and reduced carbonate saturation. Future projections indicate under saturation of aragonite, and potentially calcite, in the oceans by 2100. Calcifying organisms are those most at risk from such ocean acidification, as carbonate is vital in the biomineralisation of their calcium carbonate protective shells. This study highlights the importance of multi-generational studies to investigate how marine organisms can potentially adapt to future projected global climate change. Mytilus edulis is an economically important marine calcifier vulnerable to decreasing carbonate saturation as their shells comprise two calcium carbonate polymorphs: aragonite and calcite. M. edulis specimens were cultured under current and projected pCO2 (380, 550, 750 and 1000μatm), following 6months of experimental culture, adults produced second generation juvenile mussels. Juvenile mussel shells were examined for structural and crystallographic orientation of aragonite and calcite. At 1000μatm pCO2, juvenile mussels spawned and grown under this high pCO2 do not produce aragonite which is more vulnerable to carbonate under-saturation than calcite. Calcite and aragonite were produced at 380, 550 and 750μatm pCO2. Electron back scatter diffraction analyses reveal less constraint in crystallographic orientation with increased pCO2. Shell formation is maintained, although the nacre crystals appear corroded and crystals are not so closely layered together. The differences in ultrastructure and crystallography in shells formed by juveniles spawned from adults in high pCO2 conditions may prove instrumental in their ability to survive ocean acidification. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Instabilities in inhomogeneous plasma

    International Nuclear Information System (INIS)

    Mikhailovsky, A.B.

    1983-01-01

    The plasma inhomogeneity across the magnetic field causes a wide class of instabilities which are called instabilities of an inhomogeneous plasma or gradient instabilities. The instabilities that can be studied in the approximation of a magnetic field with parallel straight field lines are treated first, followed by a discussion of the influence of shear on these instabilities. The instabilities of a weakly inhomogeneous plasma with the Maxwellian velocity distribution of particles caused by the density and temperature gradients are often called drift instabilities, and the corresponding types of perturbations are the drift waves. An elementary theory of drift instabilities is presented, based on the simplest equations of motion of particles in the field of low-frequency and long-wavelength perturbations. Following that is a more complete theory of inhomogeneous collisionless plasma instabilities which uses the permittivity tensor and, in the case of electrostatic perturbations, the scalar of permittivity. The results are used to study the instabilities of a strongly inhomogeneous plasma. The instabilities of a plasma in crossed fields are discussed and the electromagnetic instabilities of plasma with finite and high pressure are described. (Auth.)

  17. Reducing Diesel Engine Emission Using Reactivity Controlled Approach

    Directory of Open Access Journals (Sweden)

    Osama Hasib Ghazal

    2018-01-01

    Full Text Available Several automobile manufacturers are interested in investigating of dual fuel internal combustion engines, due to high efficiencand low emissions. Many alternative fuels have been used in dual fuel mode for IC engine, such as methane, hydrogen, and natural gas. In the present study, a reactivity controlled compression ignition (RCCI engine using gasoline/diesel (G/D dual fuel has been investigated. The effectof mixing gasoline with diesel fuel on combustion characteristic, engine performance and emissions has been studied. The gasoline was injected in the engine intake port, to produce a homogeneous mixture with air. The diesel fuel was injected directly to the combustion chamber during compression stroke to initiate the combustion process. A direct injection compression ignition engine has been built and simulated using ANSYS Forte professional code. The gasoline amount in the simulation varied from (50%-80% by volume. The diesel fuel was injected to the cylinder in two stages. The model has been validated and calibrated for neat diesel fuel using available data from the literature. The results show that the heat release rate and the cylinder pressure increased when the amount of added gasoline is between 50%-60% volume of the total injected fuels, compared to the neat diesel fuel. Further addition of gasoline will have a contrary effect. In addition, the combustion duration is extended drastically when the gasoline ratio is higher than 60% which results in an incomplete combustion. The NO emission decreased drastically as the gasoline ratio increased. Moreover, addition of gasoline to the mixture increased the engine power, thermal efficienc and combustion efficienc compared to neat diesel fuel.

  18. The temporal interplay of self-esteem instability and affective instability in borderline personality disorder patients' everyday lives.

    Science.gov (United States)

    Santangelo, Philip S; Reinhard, Iris; Koudela-Hamila, Susanne; Bohus, Martin; Holtmann, Jana; Eid, Michael; Ebner-Priemer, Ulrich W

    2017-11-01

    Borderline personality disorder (BPD) is defined by a pervasive pattern of instability. Although there is ample empirical evidence that unstable self-esteem is associated with a myriad of BPD-like symptoms, self-esteem instability and its temporal dynamics have received little empirical attention in patients with BPD. Even worse, the temporal interplay of affective instability and self-esteem instability has been neglected completely, although it has been hypothesized recently that the lack of specificity of affective instability in association with BPD might be explained by the highly intertwined temporal relationship between affective and self-esteem instability. To investigate self-esteem instability, its temporal interplay with affective instability, and its association with psychopathology, 60 patients with BPD and 60 healthy controls (HCs) completed electronic diaries for 4 consecutive days during their everyday lives. Participants reported their current self-esteem, valence, and tense arousal levels 12 times a day in approximately one-hr intervals. We used multiple state-of-the-art statistical techniques and graphical approaches to reveal patterns of instability, clarify group differences, and examine the temporal interplay of self-esteem instability and affective instability. As hypothesized, instability in both self-esteem and affect was clearly elevated in the patients with BPD. In addition, self-esteem instability and affective instability were highly correlated. Both types of instability were related to general psychopathology. Because self-esteem instability could not fully explain affective instability and vice versa and neither affective instability nor self-esteem instability was able to explain psychopathology completely, our findings suggest that these types of instability represent unique facets of BPD. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  19. Faraday instability on patterned surfaces

    Science.gov (United States)

    Feng, Jie; Rubinstein, Gregory; Jacobi, Ian; Stone, Howard

    2013-11-01

    We show how micro-scale surface patterning can be used to control the onset of the Faraday instability in thin liquid films. It is well known that when a liquid film on a planar substrate is subject to sufficient vibrational accelerations, the free surface destabilizes, exhibiting a family of non-linear standing waves. This instability remains a canonical problem in the study of spontaneous pattern formation, but also has practical uses. For example, the surface waves induced by the Faraday instability have been studied as a means of enhanced damping for mechanical vibrations (Genevaux et al. 2009). Also the streaming within the unstable layer has been used as a method for distributing heterogeneous cell cultures on growth medium (Takagi et al. 2002). In each of these applications, the roughness of the substrate significantly affects the unstable flow field. We consider the effect of patterned substrates on the onset and behavior of the Faraday instability over a range of pattern geometries and feature heights where the liquid layer is thicker than the pattern height. Also, we describe a physical model for the influence of patterned roughness on the destabilization of a liquid layer in order to improve the design of practical systems which exploit the Faraday instability.

  20. Cultural diversity, economic development and societal instability

    Science.gov (United States)

    Nettle, D.; Grace, J.B.; Choisy, M.; Cornell, H.V.; Guegan, J.-F.; Hochberg, M.E.

    2007-01-01

    Background. Social scientists have suggested that cultural diversity in a nation leads to societal instability. However, societal instability may be affected not only by within-nation on ?? diversity, but also diversity between a nation and its neighbours or ?? diversity. It is also necessary to distinguish different domains of diversity, namely linguistic, ethnic and religious, and to distinguish between the direct effects of diversity on societal instability, and effects that are mediated by economic conditions. Methodology/Principal Findings. We assembled a large cross-national dataset with information on ?? and ?? cultural diversity, economic conditions, and indices of societal instability. Structural equation modeling was used to evaluate the direct and indirect effects of cultural diversity on economics and societal stability. Results show that different type and domains of diversity have interacting effects. As previously documented, linguistic ?? diversity has a negative effect on economic performance, and we show that it is largely through this economic mechanism that it affects societal instability. For ?? diversity, the higher the linguistic diversity among nations in a region, the less stable the nation. But, religious ?? diversity has the opposite effect, reducing instability, particularly in the presence of high linguistic diversity. Conclusions. Within-nation linguistic diversity is associated with reduced economic performance, which, in turn, increases societal instability. Nations which differ linguistically from their neighbors are also less stable. However, religious diversity between, neighboring nations has the opposite effect, decreasing societal instability.

  1. Cultural diversity, economic development and societal instability.

    Science.gov (United States)

    Nettle, Daniel; Grace, James B; Choisy, Marc; Cornell, Howard V; Guégan, Jean-François; Hochberg, Michael E

    2007-09-26

    Social scientists have suggested that cultural diversity in a nation leads to societal instability. However, societal instability may be affected not only by within-nation or alpha diversity, but also diversity between a nation and its neighbours or beta diversity. It is also necessary to distinguish different domains of diversity, namely linguistic, ethnic and religious, and to distinguish between the direct effects of diversity on societal instability, and effects that are mediated by economic conditions. We assembled a large cross-national dataset with information on alpha and beta cultural diversity, economic conditions, and indices of societal instability. Structural equation modeling was used to evaluate the direct and indirect effects of cultural diversity on economics and societal stability. Results show that different types and domains of diversity have interacting effects. As previously documented, linguistic alpha diversity has a negative effect on economic performance, and we show that it is largely through this economic mechanism that it affects societal instability. For beta diversity, the higher the linguistic diversity among nations in a region, the less stable the nation. But, religious beta diversity has the opposite effect, reducing instability, particularly in the presence of high linguistic diversity. Within-nation linguistic diversity is associated with reduced economic performance, which, in turn, increases societal instability. Nations which differ linguistically from their neighbors are also less stable. However, religious diversity between neighboring nations has the opposite effect, decreasing societal instability.

  2. Performance through Deformation and Instability

    Science.gov (United States)

    Bertoldi, Katia

    2015-03-01

    Materials capable of undergoing large deformations like elastomers and gels are ubiquitous in daily life and nature. An exciting field of engineering is emerging that uses these compliant materials to design active devices, such as actuators, adaptive optical systems and self-regulating fluidics. Compliant structures may significantly change their architecture in response to diverse stimuli. When excessive deformation is applied, they may eventually become unstable. Traditionally, mechanical instabilities have been viewed as an inconvenience, with research focusing on how to avoid them. Here, I will demonstrate that these instabilities can be exploited to design materials with novel, switchable functionalities. The abrupt changes introduced into the architecture of soft materials by instabilities will be used to change their shape in a sudden, but controlled manner. Possible and exciting applications include materials with unusual properties such negative Poisson's ratio, phononic crystals with tunable low-frequency acoustic band gaps and reversible encapsulation systems.

  3. Fringe instability in constrained soft elastic layers.

    Science.gov (United States)

    Lin, Shaoting; Cohen, Tal; Zhang, Teng; Yuk, Hyunwoo; Abeyaratne, Rohan; Zhao, Xuanhe

    2016-11-04

    Soft elastic layers with top and bottom surfaces adhered to rigid bodies are abundant in biological organisms and engineering applications. As the rigid bodies are pulled apart, the stressed layer can exhibit various modes of mechanical instabilities. In cases where the layer's thickness is much smaller than its length and width, the dominant modes that have been studied are the cavitation, interfacial and fingering instabilities. Here we report a new mode of instability which emerges if the thickness of the constrained elastic layer is comparable to or smaller than its width. In this case, the middle portion along the layer's thickness elongates nearly uniformly while the constrained fringe portions of the layer deform nonuniformly. When the applied stretch reaches a critical value, the exposed free surfaces of the fringe portions begin to undulate periodically without debonding from the rigid bodies, giving the fringe instability. We use experiments, theory and numerical simulations to quantitatively explain the fringe instability and derive scaling laws for its critical stress, critical strain and wavelength. We show that in a force controlled setting the elastic fingering instability is associated with a snap-through buckling that does not exist for the fringe instability. The discovery of the fringe instability will not only advance the understanding of mechanical instabilities in soft materials but also have implications for biological and engineered adhesives and joints.

  4. Model predictive control based on reduced order models applied to belt conveyor system.

    Science.gov (United States)

    Chen, Wei; Li, Xin

    2016-11-01

    In the paper, a model predictive controller based on reduced order model is proposed to control belt conveyor system, which is an electro-mechanics complex system with long visco-elastic body. Firstly, in order to design low-degree controller, the balanced truncation method is used for belt conveyor model reduction. Secondly, MPC algorithm based on reduced order model for belt conveyor system is presented. Because of the error bound between the full-order model and reduced order model, two Kalman state estimators are applied in the control scheme to achieve better system performance. Finally, the simulation experiments are shown that balanced truncation method can significantly reduce the model order with high-accuracy and model predictive control based on reduced-model performs well in controlling the belt conveyor system. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  5. Mood instability as a precursor to depressive illness: A prospective and mediational analysis.

    Science.gov (United States)

    Marwaha, Steven; Balbuena, Lloyd; Winsper, Catherine; Bowen, Rudy

    2015-06-01

    Mood instability levels are high in depression, but temporal precedence and potential mechanisms are unknown. Hypotheses tested were as follows: (1) mood instability is associated with depression cross-sectionally, (2) mood instability predicts new onset and maintenance of depression prospectively and (3) the mood instability and depression link are mediated by sleep problems, alcohol abuse and life events. Data from the National Psychiatric Morbidity Survey 2000 at baseline (N = 8580) and 18-month follow-up (N = 2413) were used. Regression modeling controlling for socio-demographic factors, anxiety and hypomanic mood was conducted. Multiple mediational analyses were used to test our conceptual path model. Mood instability was associated with depression cross-sectionally (odds ratio: 5.28; 95% confidence interval: [3.67, 7.59]; p depression inception (odds ratio: 2.43; 95% confidence interval: [1.03-5.76]; p = 0.042) after controlling for important confounders. Mood instability did not predict maintenance of depression. Sleep difficulties and severe problems with close friends and family significantly mediated the link between mood instability and new onset depression (23.05% and 6.19% of the link, respectively). Alcohol abuse and divorce were not important mediators in the model. Mood instability is a precursor of a depressive episode, predicting its onset. Difficulties in sleep are a significant part of the pathway. Interventions targeting mood instability and sleep problems have the potential to reduce the risk of depression. © The Royal Australian and New Zealand College of Psychiatrists 2015.

  6. The sensory quality of allergen-controlled, fat-reduced, salt-reduced pork-ostrich sausages during storage.

    Science.gov (United States)

    Guzek, Dominika; Głąbska, Dominika; Brodowska, Marta; Godziszewska, Jolanta; Górska-Horczyczak, Elżbieta; Pogorzelska, Ewelina; Wojtasik-Kalinowska, Iwona; Wierzbicka, Agnieszka

    2017-12-01

    New meat products tailored to consumer health should be characterised by reduced sodium, fat and cholesterol contents and other health-promoting benefits. However, the food sector's greatest challenge is allergen-free production. Consumers are not willing to compromise the sensory quality of meat products for health. The aim of the present study was to analyse the influence of the storage time on the physical properties and consumer acceptance of allergen-controlled, fat-reduced, salt-reduced pork-ostrich sausages. The study focused on pork-ostrich sausages produced in accordance with a new patented technology, which focused on eliminating cross-contamination on-line in the plant, eliminating cross-contamination after preparation, and eliminating spices with high allergy potential. The production was focused on reducing fat (by approximately 50%) and salt (by approximately 30%) levels. No changes in the texture parameters of the sausage were observed during storage time; however, some changes in colour were observed. There were no significant differences in sensory consumer acceptability of pork-ostrich sausage after 14 days of storage; thus, it may be stated that the instrumentally assessed differences in colour did not influence consumer acceptance. The applied fat and NaCl reduction in the pork-ostrich sausages contributed to high consumer ratings and was not correlated with saltiness acceptability. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  7. Wind Turbine Control Design to Reduce Capital Costs: 7 January 2009 - 31 August 2009

    Energy Technology Data Exchange (ETDEWEB)

    Darrow, P. J.

    2010-01-01

    This report first discusses and identifies which wind turbine components can benefit from advanced control algorithms and also presents results from a preliminary loads case analysis using a baseline controller. Next, it describes the design, implementation, and simulation-based testing of an advanced controller to reduce loads on those components. The case-by-case loads analysis and advanced controller design will help guide future control research.

  8. Joint Instability and Osteoarthritis

    Directory of Open Access Journals (Sweden)

    Darryl Blalock

    2015-01-01

    Full Text Available Joint instability creates a clinical and economic burden in the health care system. Injuries and disorders that directly damage the joint structure or lead to joint instability are highly associated with osteoarthritis (OA. Thus, understanding the physiology of joint stability and the mechanisms of joint instability-induced OA is of clinical significance. The first section of this review discusses the structure and function of major joint tissues, including periarticular muscles, which play a significant role in joint stability. Because the knee, ankle, and shoulder joints demonstrate a high incidence of ligament injury and joint instability, the second section summarizes the mechanisms of ligament injury-associated joint instability of these joints. The final section highlights the recent advances in the understanding of the mechanical and biological mechanisms of joint instability-induced OA. These advances may lead to new opportunities for clinical intervention in the prevention and early treatment of OA.

  9. Joint instability and osteoarthritis.

    Science.gov (United States)

    Blalock, Darryl; Miller, Andrew; Tilley, Michael; Wang, Jinxi

    2015-01-01

    Joint instability creates a clinical and economic burden in the health care system. Injuries and disorders that directly damage the joint structure or lead to joint instability are highly associated with osteoarthritis (OA). Thus, understanding the physiology of joint stability and the mechanisms of joint instability-induced OA is of clinical significance. The first section of this review discusses the structure and function of major joint tissues, including periarticular muscles, which play a significant role in joint stability. Because the knee, ankle, and shoulder joints demonstrate a high incidence of ligament injury and joint instability, the second section summarizes the mechanisms of ligament injury-associated joint instability of these joints. The final section highlights the recent advances in the understanding of the mechanical and biological mechanisms of joint instability-induced OA. These advances may lead to new opportunities for clinical intervention in the prevention and early treatment of OA.

  10. Role of microsatellite instability in colon cancer

    Directory of Open Access Journals (Sweden)

    M. Yu. Fedyanin

    2012-01-01

    Full Text Available Coloncancer is among leading causes of cancer morbidity and mortality both inRussiaand worldwide. Development of molecular biology lead to decoding of carcinogenesis and tumor progression mechanisms. These processes require accumulation of genetic and epigenetic alterations in a tumor cell.Coloncancer carcinogenesis is characterized by mutations cumulation in genes controlling growth and differentiation of epithelial cells, which leads to their genetic instability. Microsatellite instability is a type of genetic instability characterized by deterioration of mismatch DNA repair. This leads to faster accumulation of mutations in DNA. Loss of mismatch repair mechanism can easily be diagnosed by length of DNA microsatellites. These alterations are termed microsatellite instability. They can be found both in hereditary and sporadic colon cancers. This review covers the questions of microsatellite instability, its prognostic and predictive value in colon cancer.

  11. Lending sociodynamics and economic instability

    Science.gov (United States)

    Hawkins, Raymond J.

    2011-11-01

    We show how the dynamics of economic instability and financial crises articulated by Keynes in the General Theory and developed by Minsky as the Financial Instability Hypothesis can be formalized using Weidlich’s sociodynamics of opinion formation. The model addresses both the lending sentiment of a lender in isolation as well as the impact on that lending sentiment of the behavior of other lenders. The risk associated with lending is incorporated through a stochastic treatment of loan dynamics that treats prepayment and default as competing risks. With this model we are able to generate endogenously the rapid changes in lending opinion that attend slow changes in lending profitability and find these dynamics to be consistent with the rise and collapse of the non-Agency mortgage-backed securities market in 2007/2008. As the parameters of this model correspond to well-known phenomena in cognitive and social psychology, we can both explain why economic instability has proved robust to advances in risk measurement and suggest how policy for reducing economic instability might be formulated in an experimentally sound manner.

  12. Evolved finite state controller for hybrid system in reduced search space

    DEFF Research Database (Denmark)

    Dupuis, Jean-Francois; Fan, Zhun

    2009-01-01

    This paper presents an evolutionary methodology to automatically generate finite state automata (FSA) controllers to control hybrid systems. The proposed approach reduces the search space using an invariant analysis of the system. FSA controllers for a case study of two-tank system have been...

  13. Modeling and simulation of combustion chamber and propellant dynamics and issues in active control of combustion instabilities

    Science.gov (United States)

    Isella, Giorgio Carlo

    A method for a comprehensive approach to analysis of the dynamics of an actively controlled combustion chamber, with detailed analysis of the combustion models for the case of a solid rocket propellant, is presented here. The objective is to model the system as interconnected blocks describing the dynamics of the chamber, combustion and control. The analytical framework for the analysis of the dynamics of a combustion chamber is based on spatial averaging, as introduced by Culick. Combustion dynamics are analyzed for the case of a solid propellant. Quasi-steady theory is extended to include the dynamics of the gas-phase and also of a surface layer. The models are constructed so that they produce a combustion response function for the solid propellant that can be immediately introduced in the our analytical framework. The principal objective mechanisms responsible for the large sensitivity, observed experimentally, of propellant response to small variations. We show that velocity coupling, and not pressure coupling, has the potential to be the mechanism responsible for that high sensitivity. We also discuss the effect of particulate modeling on the global dynamics of the chamber and revisit the interpretation of the intrinsic stability limit for burning of solid propellants. Active control is also considered. Particular attention is devoted to the effect of time delay (between sensing and actuation); several methods to compensate for it are discussed, with numerical examples based on the approximate analysis produced by our framework. Experimental results are presented for the case of a Dump Combustor. The combustor exhibits an unstable burning mode, defined through the measurement of the pressure trace and shadowgraph imaging. The transition between stable and unstable modes of operation is characterized by the presence of hysteresis, also observed in other experimental works, and hence not a special characteristic of this combustor. Control is introduced in the

  14. Control Instabilities in a Pulsed Multi-Cavity RF System with Vector Sum Feedback (A Mathematical Analysis)

    CERN Document Server

    Tückmantel, Joachim

    2001-01-01

    Upcoming projects relying on pulsed linear accelerators intend to use superconducting RF systems. Cost reasons suggest driving several cavities by a common transmitter, controlled over a vector sum feedback system, possibly supported by a feed forward system. Numerical simulations hint that such a system may become uncontrollable under certain conditions. In the present paper, for a model very close to reality, we will present a mathematical proof that in fact spontaneous symmetry braking is possible for these configurations, defining also the precise conditions under which it will take place. These can be used as an estimate for the real RF system stability limits. The listing of a small program demonstrating the mechanism numerically for two cavities is attached.

  15. Control Instabilities in a Pulsed Multi-Cavity RF System with Vector Sum Feedback (A Mathematical Analysis) 052

    CERN Document Server

    Tückmantel, Joachim

    2001-01-01

    Upcoming projects relying on pulsed linear accelerators intend to use superconducting RF systems. Cost reasons suggest driving several cavities by a common transmitter, controlled over a vector sum feedback system, possibly supported by a feed forward system. Numerical simulations hint that such a system may become uncontrollable under certain conditions. In the present paper, for a model very close to reality, we will present a mathematical proof that in fact spontaneous symmetry braking is possible for these configurations, defining also the precise conditions under which it will take place. These can be used as an estimate for the real RF system stability limits. The listing of a small program demonstrating the mechanism numerically for two cavities is attached.

  16. Hydrodynamic instabilities in inertial fusion

    International Nuclear Information System (INIS)

    Hoffman, N.M.

    1994-01-01

    This report discusses topics on hydrodynamics instabilities in inertial confinement: linear analysis of Rayleigh-Taylor instability; ablation-surface instability; bubble rise in late-stage Rayleigh-Taylor instability; and saturation and multimode interactions in intermediate-stage Rayleigh-Taylor instability

  17. Jeans instability in a quantum dusty magnetoplasma

    International Nuclear Information System (INIS)

    Salimullah, M.; Jamil, M.; Shah, H. A.; Murtaza, G.

    2009-01-01

    Jeans instability in a homogeneous cold quantum dusty plasma in the presence of the ambient magnetic field and the quantum effect arising through the Bohm potential has been examined using the quantum magnetohydrodynamic model. It is found that the Jeans instability is significantly reduced by the presence of the dust-lower-hybrid wave and the ion quantum effect. The minimum wavenumber for Jeans stability depends clearly on ion quantum effect and the dust-lower-hybrid frequency also.

  18. Dorsoradial capsulodesis for trapeziometacarpal joint instability.

    Science.gov (United States)

    Rayan, Ghazi; Do, Viet

    2013-02-01

    We describe an alternative method for treating chronic trapeziometacarpal (TM) joint instability after acute injury or chronic repetitive use of the thumb by performing a dorsoradial capsulodesis procedure. The procedure is done by imbricating the redundant TM joint dorsoradial ligament and capsule after reducing the joint by pronating the thumb. The dorsoradial capsulodesis is a reasonable reconstructive option for chronic TM joint instability and subluxation. Copyright © 2013 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  19. Avian response to tidal freshwater habitat creation by controlled reduced tide system

    NARCIS (Netherlands)

    Beauchard, O.; Jacobs, S.; Ysebaert, T.; Meire, P.

    2013-01-01

    Human activities have caused extensive loss of estuarine wetlands, and the restoration of functional habitats remains a challenging task given several physical constraints in strongly embanked estuaries. In the Schelde estuary (Belgium), a new tidal marsh restoration technique, Controlled Reduced

  20. Notification: Implementation of Executive Order 13771, “Reducing Regulation and Controlling Regulatory Costs”

    Science.gov (United States)

    Project #OA&E-FY18-0177, April 10, 2018. The OIG plans to begin preliminary research on the Office of the Administrator's Office of Policy implementation of Executive Order 13771, Reducing Regulation and Controlling Regulatory Costs.

  1. Propellant injection strategy for suppressing acoustic combustion instability

    Science.gov (United States)

    Diao, Qina

    Shear-coaxial injector elements are often used in liquid-propellant-rocket thrust chambers, where combustion instabilities remain a significant problem. A conventional solution to the combustion instability problem relies on passive control techniques that use empirically-developed hardware such as acoustic baffles and tuned cavities. In addition to adding weight and decreasing engine performance, these devices are designed using trial-and-error methods, which do not provide the capability to predict the overall system stability characteristics in advance. In this thesis, two novel control strategies that are based on propellant fluid dynamics were investigated for mitigating acoustic instability involving shear-coaxial injector elements. The new control strategies would use a set of controlled injectors allowing local adjustment of propellant flow patterns for each operating condition, particularly when instability could become a problem. One strategy relies on reducing the oxidizer-fuel density gradient by blending heavier methane with the main fuel, hydrogen. Another strategy utilizes modifying the equivalence ratio to affect the acoustic impedance through mixing and reaction rate changes. The potential effectiveness of these strategies was assessed by conducting unit-physics experiments. Two different model combustors, one simulating a single-element injector test and the other a double-element injector test, were designed and tested for flame-acoustic interaction. For these experiments, the Reynolds number of the central oxygen jet was kept between 4700 and 5500 making the injector flames sufficiently turbulent. A compression driver, mounted on one side of the combustor wall, provided controlled acoustic excitation to the injector flames, simulating the initial phase of flame-acoustic interaction. Acoustic excitation was applied either as band-limited white noise forcing between 100 Hz and 5000 Hz or as single-frequency, fixed-amplitude forcing at 1150 Hz

  2. A Fault Detection Filtering for Networked Control Systems Based on Balanced Reduced-Order

    Directory of Open Access Journals (Sweden)

    Da-Meng Dai

    2015-01-01

    Full Text Available Due to the probability of the packet dropout in the networked control systems, a balanced reduced-order fault detection filter is proposed. In this paper, we first analyze the packet dropout effects in the networked control systems. Then, in order to obtain a robust fault detector for the packet dropout, we use the balanced structure to construct a reduced-order model for residual dynamics. Simulation results are provided to testify the proposed method.

  3. The effect of perindopril on postural instability in older people with a history of falls-a randomised controlled trial.

    Science.gov (United States)

    Sumukadas, Deepa; Price, Rosemary; McMurdo, Marion E T; Rauchhaus, Petra; Struthers, Allan; McSwiggan, Stephen; Arnold, Graham; Abboud, Rami; Witham, Miles

    2018-01-01

    double-blind, parallel group, placebo-controlled randomised trial. we recruited people aged >65 years with at least one fall in the previous year. Participants received 4 mg perindopril or placebo daily for 15 weeks. The primary outcome was the between-group difference in force-plate measured anteroposterior (AP) sway at 15 weeks. Secondary outcomes included other measures of postural sway, limits of stability during maximal forward, right and left leaning, blood pressure, muscle strength, 6-min walk distance and falls. The primary outcome was assessed using two-way ANOVA, adjusted for baseline factors. we randomised 80 participants. Mean age was 78.0 (SD 7.4) years; 60 (75%) were female. About 77/80 (96%) completed the trial. At 15 weeks there were no significant between-group differences in AP sway with eyes open (mean difference 0 mm, 95% CI -8 to 7 mm, P = 0.91) or eyes closed (mean difference 2 mm, 95% CI -7 to 12 mm, P = 0.59); no differences in other measures of postural stability, muscle strength or function. About 16/40 (42%) of patients in each group had orthostatic hypotension at follow-up. The median number (IQR) of falls was 1 (0,4) in the perindopril versus 1 (0,2) in the placebo group (P = 0.24). perindopril did not improve postural sway in older people at risk of falls. ISRCTN58995463. © The Author 2017. Published by Oxford University Press on behalf of the British Geriatrics Society.

  4. Parameterized Disturbance Observer Based Controller to Reduce Cyclic Loads of Wind Turbine

    Directory of Open Access Journals (Sweden)

    Raja M. Imran

    2018-05-01

    Full Text Available This paper is concerned with bump-less transfer of parameterized disturbance observer based controller with individual pitch control strategy to reduce cyclic loads of wind turbine in full load operation. Cyclic loads are generated due to wind shear and tower shadow effects. Multivariable disturbance observer based linear controllers are designed with objective to reduce output power fluctuation, tower oscillation and drive-train torsion using optimal control theory. Linear parameterized controllers are designed by using a smooth scheduling mechanism between the controllers. The proposed parameterized controller with individual pitch was tested on nonlinear Fatigue, Aerodynamics, Structures, and Turbulence (FAST code model of National Renewable Energy Laboratory (NREL’s 5 MW wind turbine. The closed-loop system performance was assessed by comparing the simulation results of proposed controller with a fixed gain and parameterized controller with collective pitch for full load operation of wind turbine. Simulations are performed with step wind to see the behavior of the system with wind shear and tower shadow effects. Then, turbulent wind is applied to see the smooth transition of the controllers. It can be concluded from the results that the proposed parameterized control shows smooth transition from one controller to another controller. Moreover, 3p and 6p harmonics are well mitigated as compared to fixed gain DOBC and parameterized DOBC with collective pitch.

  5. Reducing lumber thickness variation using real-time statistical process control

    Science.gov (United States)

    Thomas M. Young; Brian H. Bond; Jan Wiedenbeck

    2002-01-01

    A technology feasibility study for reducing lumber thickness variation was conducted from April 2001 until March 2002 at two sawmills located in the southern U.S. A real-time statistical process control (SPC) system was developed that featured Wonderware human machine interface technology (HMI) with distributed real-time control charts for all sawing centers and...

  6. Damage Control Automation for Reduced Manning (DC-ARM) Supervisory Control System Software Summary

    National Research Council Canada - National Science Library

    Downs, Ryan

    2002-01-01

    .... The SCS currently interfaces and controls the ship's automated fire main, outfitted with smart valves, a high-pressure water mist system, a video over IP system, a door position indication system...

  7. How to reduce workload--augmented reality to ease the work of air traffic controllers.

    Science.gov (United States)

    Hofmann, Thomas; König, Christina; Bruder, Ralph; Bergner, Jörg

    2012-01-01

    In the future the air traffic will rise--the workload of the controllers will do the same. In the BMWi research project, one of the tasks is, how to ensure safe air traffic, and a reasonable workload for the air traffic controllers. In this project it was the goal to find ways how to reduce the workload (and stress) for the controllers to allow safe air traffic, esp. at huge hub-airports by implementing augmented reality visualization and interaction.

  8. A Fuzzy Control System for Reducing Urban Runoff by a Stormwater Storage Tank

    Science.gov (United States)

    Zhang, P.; Cai, Y.; Wang, J.

    2017-12-01

    Stormwater storage tank (SST) is a popular low impact development technology for reducing stormwater runoff in the construction of sponge city. Most researches on SST were mainly the design, pollutants removal effect, and operation assessment. While there were few researches on the automatic control of SST for reducing peak flow. In this paper, fuzzy control was introduced into the peak control of SST to improve the efficiency of reducing stormawter runoff. Firstly, the design of SST was investigated. A catchment area and return period were assumed, a SST model was manufactured, and then the storage capacity of the SST was verified. Secondly, the control parameters of the SST based on reducing stormwater runoff was analyzed, and a schematic diagram of real-time control (RTC) system based on peak control SST was established. Finally, fuzzy control system of a double input (flow and water level) and double output (inlet and outlet valve) was designed. The results showed that 1) under the different return periods (one year, three years, five years), the SST had the effect of delayed peak control and storage by increasing the detention time, 2) rainfall, pipeline flow, the influent time and the water level in the SST could be used as RTC parameters, and 3) the response curves of flow velocity and water level fluctuated very little and reached equilibrium in a short time. The combination of online monitoring and fuzzy control was feasible to control the SST automatically. This paper provides a theoretical reference for reducing stormwater runoff and improving the operation efficiency of SST.

  9. Numerical study of jets secondary instabilities

    International Nuclear Information System (INIS)

    Brancher, Pierre

    1996-01-01

    The work presented in this dissertation is a contribution to the study of the transition to turbulence in open shear flows. Results from direct numerical simulations are interpreted within the framework of hydrodynamic stability theory. The first chapter is an introduction to the primary and secondary instabilities observed in jets and mixing layers. The numerical method used in the present study is detailed in the second chapter. The dynamics of homogeneous circular jets subjected to stream wise and azimuthal perturbations are investigated in the third chapter. A complete scenario describing the evolution of the jet is proposed with emphasis on the dynamics of vorticity within the flow. In the fourth chapter a parametric study reveals a three-dimensional secondary instability mainly controlled in the linear regime by the Strouhal number of the primary instability. In the nonlinear regime the dynamics of the azimuthal harmonies are described by means of model equations and are linked to the formation of stream wise vortices in the braid. The fifth chapter is dedicated to the convective or absolute nature of the secondary instabilities in plane shear layers. It is shown that there are flow configurations for which the two-dimensional secondary instability (pairing) is absolute even though the primary instability (Kelvin-Helmholtz) is convective. Some preliminary results concerning the three-dimensional secondary instabilities arc presented at the end of this chapter. The last chapter summarizes the main results and examines possible extensions of this work. (author) [fr

  10. Control Strategies to Reduce the Energy Consumption of Central Domestic Hot Water Systems

    Energy Technology Data Exchange (ETDEWEB)

    Dentz, Jordan [The Levy Partnership, Inc., New York, NY (United States). Advanced Residential Integrated Energy Solutions; Ansanelli, Eric [The Levy Partnership, Inc., New York, NY (United States). Advanced Residential Integrated Energy Solutions; Henderson, Hugh [The Levy Partnership, Inc., New York, NY (United States). Advanced Residential Integrated Energy Solutions; Varshney, Kapil [The Levy Partnership, Inc., New York, NY (United States). Advanced Residential Integrated Energy Solutions

    2016-06-23

    Domestic hot water (DHW) heating is the second largest energy end use in U.S. buildings, exceeded only by space conditioning. Recirculation systems consisting of a pump and piping loop(s) are commonly used in multifamily buildings to reduce wait time for hot water at faucets; however, constant pumping increases energy consumption by exposing supply and return line piping to continuous heat loss, even during periods when there is no demand for hot water. In this study, ARIES installed and tested two types of recirculation controls in a pair of buildings in order to evaluate their energy savings potential. Demand control, temperature modulation controls, and the simultaneous operation of both were compared to the baseline case of constant recirculation. Additionally, interactive effects between DHW control fuel reductions and space conditioning (heating and cooling) were estimated in order to make more realistic predictions of the payback and financial viability of retrofitting DHW systems with these controls. Results showed that DHW fuel consumption reduced by 7% after implementing the demand control technique, 2% after implementing temperature modulation, and 15% after implementing demand control and temperature modulation techniques simultaneously; recirculation pump runtime was reduced to 14 minutes or less per day. With space heating and cooling interactions included, the estimated annual cost savings were 8%, 1%, and 14% for the respective control techniques. Possible complications in the installation, commissioning and operation of the controls were identified and solutions offered.

  11. Control Strategies to Reduce the Energy Consumption of Central Domestic Hot Water Systems

    Energy Technology Data Exchange (ETDEWEB)

    Dentz, Jordan; Ansanelli, Eric; Henderson, Hugh; Varshney, Kapil

    2016-06-03

    Domestic hot water (DHW) heating is the second largest energy end use in U.S. buildings, exceeded only by space conditioning. Recirculation systems consisting of a pump and piping loop(s) are commonly used in multifamily buildings to reduce wait time for hot water at faucets; however, constant pumping increases energy consumption by exposing supply and return line piping to continuous heat loss, even during periods when there is no demand for hot water. In this study, ARIES installed and tested two types of recirculation controls in a pair of buildings in order to evaluate their energy savings potential. Demand control, temperature modulation controls, and the simultaneous operation of both were compared to the baseline case of constant recirculation. Additionally, interactive effects between DHW control fuel reductions and space conditioning (heating and cooling) were estimated in order to make more realistic predictions of the payback and financial viability of retrofitting DHW systems with these controls. Results showed that DHW fuel consumption reduced by 7% after implementing the demand control technique, 2% after implementing temperature modulation, and 15% after implementing demand control and temperature modulation techniques simultaneously; recirculation pump runtime was reduced to 14 minutes or less per day. With space heating and cooling interactions included, the estimated annual cost savings were 8%, 1%, and 14% for the respective control techniques. Possible complications in the installation, commissioning and operation of the controls were identified and solutions offered.

  12. Design of COSMIC: a randomized, multi-centre controlled trial comparing conservative or early surgical management of incomplete cervical cord syndrome without spinal instability.

    Science.gov (United States)

    Bartels, Ronald H M A; Hosman, Allard J F; van de Meent, Henk; Hofmeijer, Jeannette; Vos, Pieter E; Slooff, Willem Bart; Öner, F Cumhur; Coppes, Maarten H; Peul, Wilco C; Verbeek, André L M

    2013-01-31

    Incomplete cervical cord syndrome without spinal instability is a very devastating event for the patient and the family. It is estimated that up to 25% of all traumatic spinal cord lesions belong to this category. The treatment for this type of spinal cord lesion is still subject of discussion. From a biological point of view early surgery could prevent secondary damage due to ongoing compression of the already damaged spinal cord. Historically, however, conservative treatment was propagated with good clinical results. Proponents for early surgery as well those favoring conservative treatment are still in debate. The proposed trial will contribute to the discussion and hopefully also to a decrease in the variability of clinical practice. A randomized controlled trial is designed to compare the clinical outcome of early surgical strategy versus a conservative approach. The primary outcome is clinical outcome according to mJOA. This also measured by ASIA score, DASH score and SCIM III score. Other endpoints are duration of the stay at a high care department (medium care, intensive care), duration of the stay at the hospital, complication rate, mortality rate, sort of rehabilitation, and quality of life. A sample size of 36 patients per group was calculated to reach a power of 95%. The data will be analyzed as intention-to-treat at regular intervals, but the end evaluation will take place at two years post-injury. At the end of the study, clinical outcomes between treatments attitudes can be compared. Efficacy, but also efficiency can be determined. A goal of the study is to determine which treatment will result in the best quality of life for the patients. This study will certainly contribute to more uniformity of treatment offered to patients with a special sort of spinal cord injury. Gov: NCT01367405.

  13. Controlling the numerical Cerenkov instability in PIC simulations using a customized finite difference Maxwell solver and a local FFT based current correction

    International Nuclear Information System (INIS)

    Li, Fei; Yu, Peicheng; Xu, Xinlu; Fiuza, Frederico; Decyk, Viktor K.

    2017-01-01

    In this study we present a customized finite-difference-time-domain (FDTD) Maxwell solver for the particle-in-cell (PIC) algorithm. The solver is customized to effectively eliminate the numerical Cerenkov instability (NCI) which arises when a plasma (neutral or non-neutral) relativistically drifts on a grid when using the PIC algorithm. We control the EM dispersion curve in the direction of the plasma drift of a FDTD Maxwell solver by using a customized higher order finite difference operator for the spatial derivative along the direction of the drift (1^ direction). We show that this eliminates the main NCI modes with moderate |k_1|, while keeps additional main NCI modes well outside the range of physical interest with higher |k_1|. These main NCI modes can be easily filtered out along with first spatial aliasing NCI modes which are also at the edge of the fundamental Brillouin zone. The customized solver has the possible advantage of improved parallel scalability because it can be easily partitioned along 1^ which typically has many more cells than other directions for the problems of interest. We show that FFTs can be performed locally to current on each partition to filter out the main and first spatial aliasing NCI modes, and to correct the current so that it satisfies the continuity equation for the customized spatial derivative. This ensures that Gauss’ Law is satisfied. Lastly, we present simulation examples of one relativistically drifting plasma, of two colliding relativistically drifting plasmas, and of nonlinear laser wakefield acceleration (LWFA) in a Lorentz boosted frame that show no evidence of the NCI can be observed when using this customized Maxwell solver together with its NCI elimination scheme.

  14. Design of COSMIC: a randomized, multi-centre controlled trial comparing conservative or early surgical management of incomplete cervical cord syndrome without spinal instability

    Directory of Open Access Journals (Sweden)

    Bartels Ronald HMA

    2013-01-01

    Full Text Available Abstract Background Incomplete cervical cord syndrome without spinal instability is a very devastating event for the patient and the family. It is estimated that up to 25% of all traumatic spinal cord lesions belong to this category. The treatment for this type of spinal cord lesion is still subject of discussion. From a biological point of view early surgery could prevent secondary damage due to ongoing compression of the already damaged spinal cord. Historically, however, conservative treatment was propagated with good clinical results. Proponents for early surgery as well those favoring conservative treatment are still in debate. The proposed trial will contribute to the discussion and hopefully also to a decrease in the variability of clinical practice. Methods/Design A randomized controlled trial is designed to compare the clinical outcome of early surgical strategy versus a conservative approach. The primary outcome is clinical outcome according to mJOA. This also measured by ASIA score, DASH score and SCIM III score. Other endpoints are duration of the stay at a high care department (medium care, intensive care, duration of the stay at the hospital, complication rate, mortality rate, sort of rehabilitation, and quality of life. A sample size of 36 patients per group was calculated to reach a power of 95%. The data will be analyzed as intention-to-treat at regular intervals, but the end evaluation will take place at two years post-injury. Discussion At the end of the study, clinical outcomes between treatments attitudes can be compared. Efficacy, but also efficiency can be determined. A goal of the study is to determine which treatment will result in the best quality of life for the patients. This study will certainly contribute to more uniformity of treatment offered to patients with a special sort of spinal cord injury. Trial Registration Gov: NCT01367405

  15. Relativistic gravitational instabilities

    International Nuclear Information System (INIS)

    Schutz, B.F.

    1987-01-01

    The purpose of these lectures is to review and explain what is known about the stability of relativistic stars and black holes, with particular emphases on two instabilities which are due entirely to relativistic effects. The first of these is the post-Newtonian pulsational instability discovered independently by Chandrasekhar (1964) and Fowler (1964). This effectively ruled out the then-popular supermassive star model for quasars, and it sets a limit to the central density of white dwarfs. The second instability was also discovered by Chandrasekhar (1970): the gravitational wave induced instability. This sets an upper bound on the rotation rate of neutron stars, which is near that of the millisecond pulsar PSR 1937+214, and which is beginning to constrain the equation of state of neutron matter. 111 references, 5 figures

  16. Character of decay instability

    International Nuclear Information System (INIS)

    Polovin, R.V.; Demutskii, V.P.

    1981-01-01

    If the initial wave is unstable in the upper half plane Im ω>0 and there are no branch points of the quasiwave number, or if waves traveling in the same direction coalesce at a branch point, the instability is convective. On the other hand, if a branch point k(ω) does exist in the upper half-plane Im ω>0, and not all the waves that merge at this point travel in the same direction, the instability is absolute. A Green's function that describes the evolution of the perturbations of the initial wave in space and in time is constructed. The growth rates of the decay instability of the harmonics are determined. The produced waves are richer in harmonics than the initial waves. It is shown that the decay instability of an Alfven wave is absolute

  17. Spondylolisthesis and Posterior Instability

    International Nuclear Information System (INIS)

    Niggemann, P.; Beyer, H.K.; Frey, H.; Grosskurth, D.; Simons, P.; Kuchta, J.

    2009-01-01

    We present the case of a patient with a spondylolisthesis of L5 on S1 due to spondylolysis at the level L5/S1. The vertebral slip was fixed and no anterior instability was found. Using functional magnetic resonance imaging (MRI) in an upright MRI scanner, posterior instability at the level of the spondylolytic defect of L5 was demonstrated. A structure, probably the hypertrophic ligament flava, arising from the spondylolytic defect was displaced toward the L5 nerve root, and a bilateral contact of the displaced structure with the L5 nerve root was shown in extension of the spine. To our knowledge, this is the first case described of posterior instability in patients with spondylolisthesis. The clinical implications of posterior instability are unknown; however, it is thought that this disorder is common and that it can only be diagnosed using upright MRI

  18. Spondylolisthesis and Posterior Instability

    Energy Technology Data Exchange (ETDEWEB)

    Niggemann, P.; Beyer, H.K.; Frey, H.; Grosskurth, D. (Privatpraxis fuer Upright MRT, Koeln (Germany)); Simons, P.; Kuchta, J. (Media Park Klinik, Koeln (Germany))

    2009-04-15

    We present the case of a patient with a spondylolisthesis of L5 on S1 due to spondylolysis at the level L5/S1. The vertebral slip was fixed and no anterior instability was found. Using functional magnetic resonance imaging (MRI) in an upright MRI scanner, posterior instability at the level of the spondylolytic defect of L5 was demonstrated. A structure, probably the hypertrophic ligament flava, arising from the spondylolytic defect was displaced toward the L5 nerve root, and a bilateral contact of the displaced structure with the L5 nerve root was shown in extension of the spine. To our knowledge, this is the first case described of posterior instability in patients with spondylolisthesis. The clinical implications of posterior instability are unknown; however, it is thought that this disorder is common and that it can only be diagnosed using upright MRI.

  19. Implementation of internal model based control and individual pitch control to reduce fatigue loads and tower vibrations in wind turbines

    Science.gov (United States)

    Mohammadi, Ebrahim; Fadaeinedjad, Roohollah; Moschopoulos, Gerry

    2018-05-01

    Vibration control and fatigue loads reduction are important issues in large-scale wind turbines. Identifying the vibration frequencies and tuning dampers and controllers at these frequencies are major concerns in many control methods. In this paper, an internal model control (IMC) method with an adaptive algorithm is implemented to first identify the vibration frequency of the wind turbine tower and then to cancel the vibration signal. Standard individual pitch control (IPC) is also implemented to compare the performance of the controllers in term of fatigue loads reduction. Finally, the performance of the system when both controllers are implemented together is evaluated. Simulation results demonstrate that using only IMC or IPC alone has advantages and can reduce fatigue loads on specific components. IMC can identify and suppress tower vibrations in both fore-aft and side-to-side directions, whereas, IPC can reduce fatigue loads on blades, shaft and yaw bearings. When both IMC and IPC are implemented together, the advantages of both controllers can be used. The aforementioned analysis and comparisons were not studied in literature and this study fills this gap. FAST, AreoDyn and Simulink are used to simulate the mechanical, aerodynamic and electrical aspects of wind turbine.

  20. Adaptive synchronization of fractional Lorenz systems using a reduced number of control signals and parameters

    International Nuclear Information System (INIS)

    Aguila-Camacho, Norelys; Duarte-Mermoud, Manuel A.; Delgado-Aguilera, Efredy

    2016-01-01

    This paper analyzes the synchronization of two fractional Lorenz systems in two cases: the first one considering fractional Lorenz systems with unknown parameters, and the second one considering known upper bounds on some of the fractional Lorenz systems parameters. The proposed control strategies use a reduced number of control signals and control parameters, employing mild assumptions. The stability of the synchronization errors is analytically demonstrated in all cases, and the convergence to zero of the synchronization errors is analytically proved in the case when the upper bounds on some system parameters are assumed to be known. Simulation studies are presented, which allows verifying the effectiveness of the proposed control strategies.

  1. Streaming gravity mode instability

    International Nuclear Information System (INIS)

    Wang Shui.

    1989-05-01

    In this paper, we study the stability of a current sheet with a sheared flow in a gravitational field which is perpendicular to the magnetic field and plasma flow. This mixing mode caused by a combined role of the sheared flow and gravity is named the streaming gravity mode instability. The conditions of this mode instability are discussed for an ideal four-layer model in the incompressible limit. (author). 5 refs

  2. Genomic instability and radiation

    Energy Technology Data Exchange (ETDEWEB)

    Little, John B [Harvard School of Public Health, Boston, MA 02115 (United States)

    2003-06-01

    Genomic instability is a hallmark of cancer cells, and is thought to be involved in the process of carcinogenesis. Indeed, a number of rare genetic disorders associated with a predisposition to cancer are characterised by genomic instability occurring in somatic cells. Of particular interest is the observation that transmissible instability can be induced in somatic cells from normal individuals by exposure to ionising radiation, leading to a persistent enhancement in the rate at which mutations and chromosomal aberrations arise in the progeny of the irradiated cells after many generations of replication. If such induced instability is involved in radiation carcinogenesis, it would imply that the initial carcinogenic event may not be a rare mutation occurring in a specific gene or set of genes. Rather, radiation may induce a process of instability in many cells in a population, enhancing the rate at which the multiple gene mutations necessary for the development of cancer may arise in a given cell lineage. Furthermore, radiation could act at any stage in the development of cancer by facilitating the accumulation of the remaining genetic events required to produce a fully malignant tumour. The experimental evidence for such induced instability is reviewed. (review)

  3. Genomic instability and radiation

    International Nuclear Information System (INIS)

    Little, John B

    2003-01-01

    Genomic instability is a hallmark of cancer cells, and is thought to be involved in the process of carcinogenesis. Indeed, a number of rare genetic disorders associated with a predisposition to cancer are characterised by genomic instability occurring in somatic cells. Of particular interest is the observation that transmissible instability can be induced in somatic cells from normal individuals by exposure to ionising radiation, leading to a persistent enhancement in the rate at which mutations and chromosomal aberrations arise in the progeny of the irradiated cells after many generations of replication. If such induced instability is involved in radiation carcinogenesis, it would imply that the initial carcinogenic event may not be a rare mutation occurring in a specific gene or set of genes. Rather, radiation may induce a process of instability in many cells in a population, enhancing the rate at which the multiple gene mutations necessary for the development of cancer may arise in a given cell lineage. Furthermore, radiation could act at any stage in the development of cancer by facilitating the accumulation of the remaining genetic events required to produce a fully malignant tumour. The experimental evidence for such induced instability is reviewed. (review)

  4. Snack purchasing is healthier when the cognitive demands of choice are reduced: A randomized controlled trial.

    Science.gov (United States)

    Allan, Julia L; Johnston, Marie; Campbell, Neil

    2015-07-01

    Individuals with inefficient executive (higher level cognitive) function have a reduced ability to resist dietary temptation. The present study aimed to design and test a theory-based point-of-purchase intervention for coffee shops that reduced the calorie content of customers' purchases by reducing the need for executive function (EF) at the moment of choice. Key facets of EF were identified by a multidisciplinary group and used to develop a point-of-purchase intervention (signage). This intervention was evaluated in a randomized controlled trial (RCT) in a public coffee shop on consumer purchases of >20,000 snacks and drinks over 12 weeks. A sample of customers (n = 128) was recruited to complete an embedded cross-sectional study measuring EF strength, dietary intentions, typical purchases, and purchases made after exposure to the intervention. The proportion of snack purchases that were high in calorie reduced significantly (t(10) = 2.34, p = .04) in intervention weeks relative to control. High calorie drink purchases were also lower in intervention than control weeks, however, this difference was not significant (t(10) = 1.56, p = .15). On average, customers purchased items containing 66 calories customer behavior increased as EF strength decreased (β = .24, p = .03). The calorie content of cafe purchases can be lowered by reducing the cognitive demands of healthy food choice at the moment of purchase, especially in those with poor EF. Environmental changes like these have the potential to help achieve population weight control. (c) 2015 APA, all rights reserved.

  5. Engineering control technologies to reduce occupational silica exposures in masonry cutting and tuckpointing.

    Science.gov (United States)

    Meeker, John D; Cooper, Michael R; Lefkowitz, Daniel; Susi, Pam

    2009-01-01

    A number of tasks in construction generate worker overexposures to respirable crystalline silica dust, which is a significant contributor to occupational mortality and morbidity. This study evaluated the performance of commercially available engineering controls used in dusty construction tasks commonly performed by bricklayers. Local exhaust ventilation (LEV) controls for a portable abrasive cutter and for tuckpointing grinders were examined at a bricklayers' training center, as were two stationary wet saws. Personal breathing zone air samples were collected with and without the use of LEV or water suppression during simulated concrete block cutting, brick cutting, and tuckpointing. Compared with the use of no exposure control during block and brick cutting, the portable LEV unit significantly reduced mean respirable quartz exposures by 96% for block cutting and 91% for brick cutting (p controls (p control and no-control scenarios. These reductions with commercially available off-the-shelf tools demonstrate the effectiveness of engineering control interventions to reduce crystalline silica exposures in construction. Strategies to further improve control performance and approaches for increasing control interventions in construction are needed.

  6. Design of COSMIC: a randomized, multi-centre controlled trial comparing conservative or early surgical management of incomplete cervical cord syndrome without spinal instability

    NARCIS (Netherlands)

    Bartels, R.H.M.; Hosman, A.J.F.; Meent, H.; Hofmeijer, Jeannette; Vos, P.E.; Slooff, W.B.; Öner, F.C.; Coppes, M.H.; Peul, W.C.; Verbeek, A.L.M.

    2013-01-01

    Background Incomplete cervical cord syndrome without spinal instability is a very devastating event for the patient and the family. It is estimated that up to 25 % of all traumatic spinal cord lesions belong to this category. The treatment for this type of spinal cord lesion is still subject of

  7. Design of COSMIC: a randomized, multi-centre controlled trial comparing conservative or early surgical management of incomplete cervical cord syndrome without spinal instability

    NARCIS (Netherlands)

    Bartels, R.H.M.A.; Hosman, A.J.F.; Meent, H. van de; Hofmeijer, J.; Vos, P.E.; Slooff, W.B.; Oner, F.C.; Coppes, M.H.; Peul, W.C.; Verbeek, A.L.M.

    2013-01-01

    ABSTRACT: BACKGROUND: Incomplete cervical cord syndrome without spinal instability is a very devastating event for the patient and the family. It is estimated that up to 25% of all traumatic spinal cord lesions belong to this category. The treatment for this type of spinal cord lesion is still

  8. An optimal control model for reducing and trading of carbon emissions

    Science.gov (United States)

    Guo, Huaying; Liang, Jin

    2016-03-01

    A stochastic optimal control model of reducing and trading for carbon emissions is established in this paper. With considerations of reducing the carbon emission growth and the price of the allowances in the market, an optimal policy is searched to have the minimum total costs to achieve the agreement of emission reduction targets. The model turns to a two-dimension HJB equation problem. By the methods of reducing dimension and Cole-Hopf transformation, a semi-closed form solution of the corresponding HJB problem under some assumptions is obtained. For more general cases, the numerical calculations, analysis and comparisons are presented.

  9. Reducing Turbine Mechanical Loads Using Flow Model-Based Wind Farm Controller

    DEFF Research Database (Denmark)

    Kazda, Jonas; Cutululis, Nicolaos Antonio

    Cumulated O&M costs of offshore wind farms are comparable with wind turbine CAPEX of such wind farm. In wind farms, wake effects can result in up to 80% higher fatigue loads at downstream wind turbines [1] and consequently larger O&M costs. The present work therefore investigates to reduce...... these loads during the provision of grid balancing services using optimal model-based wind farm control. Wind farm controllers coordinate the operating point of wind turbines in a wind farm in order to achieve a given objective. The investigated objective of the control in this work is to follow a total wind...... farm power reference while reducing the tower bending moments of the turbines in the wind farm. The wind farm controller is tested on a 8 turbine array, which is representative of a typical offshore wind farm. The operation of the wind farm is simulated using the dynamic wind farm simulation tool S imWind...

  10. To reduce the global burden of human schistosomiasis, use ‘old fashioned’ snail control

    Science.gov (United States)

    Sokolow, Susanne H.; Wood, Chelsea L.; Jones, Isabel J.; Lafferty, Kevin D.; Kuris, Armand; Hsieh, Michael H.; De Leo, Giulio A.

    2018-01-01

    Control strategies to reduce human schistosomiasis have evolved from ‘snail picking’ campaigns, a century ago, to modern wide-scale human treatment campaigns, or preventive chemotherapy. Unfortunately, despite the rise in preventive chemotherapy campaigns, just as many people suffer from schistosomiasis today as they did 50 years ago. Snail control can complement preventive chemotherapy by reducing the risk of transmission from snails to humans. Here, we present ideas for modernizing and scaling up snail control, including spatiotemporal targeting, environmental diagnostics, better molluscicides, new technologies (e.g., gene drive), and ‘outside the box’ strategies such as natural enemies, traps, and repellants. We conclude that, to achieve the World Health Assembly’s stated goal to eliminate schistosomiasis, it is time to give snail control another look.

  11. Regime-based supervisory control to reduce power fluctuations from offshore wind power plants

    DEFF Research Database (Denmark)

    Barahona Garzón, Braulio; Cutululis, Nicolaos Antonio; Trombe, Pierre-Julien

    2013-01-01

    Wind power fluctuations, especially offshore, can pose challenges in the secure and stable operation of the power system. In modern large offshore wind farms, there are supervisory controls designed to reduce the power fluctuations. Their operation is limited due to the fact that they imply loss...... that consider different wind power regimes to derive control setpoints by using a Markov-Switching AutoRegressive model. We evaluate the performance versus measured data in terms of power ramp characteristics and energy efficiency....

  12. Delay-feedback control strategy for reducing CO2 emission of traffic flow system

    Science.gov (United States)

    Zhang, Li-Dong; Zhu, Wen-Xing

    2015-06-01

    To study the signal control strategy for reducing traffic emission theoretically, we first presented a kind of discrete traffic flow model with relative speed term based on traditional coupled map car-following model. In the model, the relative speed difference between two successive running cars is incorporated into following vehicle's acceleration running equation. Then we analyzed its stability condition with discrete control system stability theory. Third, we designed a delay-feedback controller to suppress traffic jam and decrease traffic emission based on modern controller theory. Last, numerical simulations are made to support our theoretical results, including the comparison of models' stability analysis, the influence of model type and signal control on CO2 emissions. The results show that the temporal behavior of our model is superior to other models, and the traffic signal controller has good effect on traffic jam suppression and traffic CO2 emission, which fully supports the theoretical conclusions.

  13. Combustion instability modeling and analysis

    Energy Technology Data Exchange (ETDEWEB)

    Santoro, R.J.; Yang, V.; Santavicca, D.A. [Pennsylvania State Univ., University Park, PA (United States); Sheppard, E.J. [Tuskeggee Univ., Tuskegee, AL (United States). Dept. of Aerospace Engineering

    1995-12-31

    It is well known that the two key elements for achieving low emissions and high performance in a gas turbine combustor are to simultaneously establish (1) a lean combustion zone for maintaining low NO{sub x} emissions and (2) rapid mixing for good ignition and flame stability. However, these requirements, when coupled with the short combustor lengths used to limit the residence time for NO formation typical of advanced gas turbine combustors, can lead to problems regarding unburned hydrocarbons (UHC) and carbon monoxide (CO) emissions, as well as the occurrence of combustion instabilities. The concurrent development of suitable analytical and numerical models that are validated with experimental studies is important for achieving this objective. A major benefit of the present research will be to provide for the first time an experimentally verified model of emissions and performance of gas turbine combustors. The present study represents a coordinated effort between industry, government and academia to investigate gas turbine combustion dynamics. Specific study areas include development of advanced diagnostics, definition of controlling phenomena, advancement of analytical and numerical modeling capabilities, and assessment of the current status of our ability to apply these tools to practical gas turbine combustors. The present work involves four tasks which address, respectively, (1) the development of a fiber-optic probe for fuel-air ratio measurements, (2) the study of combustion instability using laser-based diagnostics in a high pressure, high temperature flow reactor, (3) the development of analytical and numerical modeling capabilities for describing combustion instability which will be validated against experimental data, and (4) the preparation of a literature survey and establishment of a data base on practical experience with combustion instability.

  14. Telomere-mediated chromosomal instability triggers TLR4 induced inflammation and death in mice.

    Directory of Open Access Journals (Sweden)

    Rabindra N Bhattacharjee

    Full Text Available BACKGROUND: Telomeres are essential to maintain chromosomal stability. Cells derived from mice lacking telomerase RNA component (mTERC-/- mice display elevated telomere-mediated chromosome instability. Age-dependent telomere shortening and associated chromosome instability reduce the capacity to respond to cellular stress occurring during inflammation and cancer. Inflammation is one of the important risk factors in cancer progression. Controlled innate immune responses mediated by Toll-like receptors (TLR are required for host defense against infection. Our aim was to understand the role of chromosome/genome instability in the initiation and maintenance of inflammation. METHODOLOGY/PRINCIPAL FINDINGS: We examined the function of TLR4 in telomerase deficient mTERC-/- mice harbouring chromosome instability which did not develop any overt immunological disorder in pathogen-free condition or any form of cancers at this stage. Chromosome instability was measured in metaphase spreads prepared from wildtype (mTERC+/+, mTERC+/- and mTERC-/- mouse splenocytes. Peritoneal and/or bone marrow-derived macrophages were used to examine the responses of TLR4 by their ability to produce inflammatory mediators TNFalpha and IL6. Our results demonstrate that TLR4 is highly up-regulated in the immune cells derived from telomerase-null (mTERC-/- mice and lipopolysaccharide, a natural ligand for TLR4 stabilises NF-kappaB binding to its promoter by down-regulating ATF-3 in mTERC-/- macrophages. CONCLUSIONS/SIGNIFICANCE: Our findings implied that background chromosome instability in the cellular level stabilises the action of TLR4-induced NF-kappaB action and sensitises cells to produce excess pro-inflammatory mediators. Chromosome/genomic instability data raises optimism for controlling inflammation by non-toxic TLR antagonists among high-risk groups.

  15. Application of a PID controller based on fuzzy logic to reduce variations in the control parameters in PWR reactors

    International Nuclear Information System (INIS)

    Vasconcelos, Wagner Eustaquio de; Lira, Carlos Alberto Brayner de Oliveira; Brito, Thiago Souza Pereira de; Afonso, Antonio Claudio Marques; Cruz Filho, Antonio Jose da; Marques, Jose Antonio; Teixeira, Marcello Goulart

    2013-01-01

    Nuclear reactors are in nature nonlinear systems and their parameters vary with time as a function of power level. These characteristics must be considered if large power variations occur in power plant operational regimes, such as in load-following conditions. A PWR reactor has a component called pressurizer, whose function is to supply the necessary high pressure for its operation and to contain pressure variations in the primary cooling system. The use of control systems capable of reducing fast variations of the operation variables and to maintain the stability of this system is of fundamental importance. The best-known controllers used in industrial control processes are proportional-integral-derivative (PID) controllers due to their simple structure and robust performance in a wide range of operating conditions. However, designing a fuzzy controller is seen to be a much less difficult task. Once a Fuzzy Logic controller is designed for a particular set of parameters of the nonlinear element, it yields satisfactory performance for a range of these parameters. The objective of this work is to develop fuzzy proportional-integral-derivative (fuzzy-PID) control strategies to control the level of water in the reactor. In the study of the pressurizer, several computer codes are used to simulate its dynamic behavior. At the fuzzy-PID control strategy, the fuzzy logic controller is exploited to extend the finite sets of PID gains to the possible combinations of PID gains in stable region. Thus the fuzzy logic controller tunes the gain of PID controller to adapt the model with changes in the water level of reactor. The simulation results showed a favorable performance with the use to fuzzy-PID controllers. (author)

  16. New Designs of Reduced-Order Observer-Based Controllers for Singularly Perturbed Linear Systems

    Directory of Open Access Journals (Sweden)

    Heonjong Yoo

    2017-01-01

    Full Text Available The slow and fast reduced-order observers and reduced-order observer-based controllers are designed by using the two-stage feedback design technique for slow and fast subsystems. The new designs produce an arbitrary order of accuracy, while the previously known designs produce the accuracy of O(ϵ only where ϵ is a small singular perturbation parameter. Several cases of reduced-order observer designs are considered depending on the measured state space variables: only all slow variables are measured, only all fast variables are measured, and some combinations of the slow and fast variables are measured. Since the two-stage methods have been used to overcome the numerical ill-conditioning problem for Cases (III–(V, they have similar procedures. The numerical ill-conditioning problem is avoided so that independent feedback controllers can be applied to each subsystem. The design allows complete time-scale separation for both the reduced-order observer and controller through the complete and exact decomposition into slow and fast time scales. This method reduces both offline and online computations.

  17. ENGINEERING CONTROL PRACTICES FOR REDUCING EMISSIONS DURING DRILLING OF ASBESTOS-CONTAINING FLOORING MATERIALS

    Science.gov (United States)

    This report describes the implementation and testing of control measures to reduce airborne asbestos generated by the drilling of asbestos-containing flooring materials, an OSHA Class III asbestos maintenance activity. Bosch 11224 and 11222 rotary drills were fitted with shrouds ...

  18. Mine Waste Technology Program. In Situ Source Control Of Acid Generation Using Sulfate-Reducing Bacteria

    Science.gov (United States)

    This report summarizes the results of the Mine Waste Technology Program (MWTP) Activity III, Project 3, In Situ Source Control of Acid Generation Using Sulfate-Reducing Bacteria, funded by the U.S. Environmental Protection Agency (EPA) and jointly administered by EPA and the U.S....

  19. Maternal Dietary Counseling Reduces Consumption of Energy-Dense Foods among Infants: A Randomized Controlled Trial

    Science.gov (United States)

    Vitolo, Marcia Regina; Bortolini, Gisele Ane; Campagnolo, Paula Dal Bo; Hoffman, Daniel J.

    2012-01-01

    Objective: To evaluate the impact of a dietary counseling in reducing the intake of energy-dense foods by infants. Design: A randomized controlled trial. Setting and Participants: Sao Leopoldo, Brazil. Mothers and infants of a low-income-group population were randomized into intervention (n = 163) and received dietary counseling during 10 home…

  20. Sulfide response analysis for sulfide control using a pS electrode in sulfate reducing bioreactors

    NARCIS (Netherlands)

    Villa Gomez, D.K.; Cassidy, J.; Keesman, K.J.; Sampaio, R.M.; Lens, P.N.L.

    2014-01-01

    Step changes in the organic loading rate (OLR) through variations in the influent chemical oxygen demand (CODin) concentration or in the hydraulic retention time (HRT) at constant COD/SO4 2- ratio (0.67) were applied to create sulfide responses for the design of a sulfide control in sulfate reducing

  1. Cognitive Behavioral Therapy Reduces Suicidal Ideation in Schizophrenia: Results from a Randomized Controlled Trial

    Science.gov (United States)

    Bateman, Katy; Hansen, Lars; Turkington, Douglas; Kingdon, David

    2007-01-01

    Patients with schizophrenia are at high risk of suicide. Cognitive behavior therapy (CBT) has been shown to reduce symptoms in schizophrenia. This study examines whether CBT also changes the level of suicidal ideation in patients with schizophrenia compared to a control group. Ninety ambulatory patients with symptoms of schizophrenia resistant to…

  2. Developing Automatic Water Table Control System for Reducing Greenhouse Gas Emissions from Paddy Fields

    Science.gov (United States)

    Arif, C.; Fauzan, M. I.; Satyanto, K. S.; Budi, I. S.; Masaru, M.

    2018-05-01

    Water table in rice fields play important role to mitigate greenhouse gas (GHG) emissions from paddy fields. Continuous flooding by maintenance water table 2-5 cm above soil surface is not effective and release more GHG emissions. System of Rice Intensification (SRI) as alternative rice farming apply intermittent irrigation by maintaining lower water table is proven can reduce GHG emissions reducing productivity significantly. The objectives of this study were to develop automatic water table control system for SRI application and then evaluate the performances. The control system was developed based on fuzzy logic algorithms using the mini PC of Raspberry Pi. Based on laboratory and field tests, the developed system was working well as indicated by lower MAPE (mean absolute percentage error) values. MAPE values for simulation and field tests were 16.88% and 15.80%, respectively. This system can save irrigation water up to 42.54% without reducing productivity significantly when compared to manual irrigation systems.

  3. Management and control aimed at reducing potential exposure of cobalt irradiation units

    International Nuclear Information System (INIS)

    Yan Yukui

    2003-01-01

    This paper is intended to address the problems of the management and control of potential exposure of cobalt irradiation units and analyze both the current situation and the resultant accident reasons associated with irradiation units, with the necessary control measures provided to reduce potential exposure. The concepts of defense in depth and excellent engineering practice are introduced in design to provide the units with sufficient redundancy. In the course of scientific management, the qualified applicants or registers devoted, strictly and effectively, their oversight, monitoring and regulation to the irradiation units. The effective management and control are achieved through safety analysis and assessment, reasonable regulatory system and source decommissioning system. (authors)

  4. Affective instability as a clinical feature of avoidant personality disorder.

    Science.gov (United States)

    Snir, Avigal; Bar-Kalifa, Eran; Berenson, Kathy R; Downey, Geraldine; Rafaeli, Eshkol

    2017-10-01

    The current study's main goal was to examine whether affective instability is elevated among individuals suffering from avoidant personality disorder (APD) by comparing it to the affective instability found among individuals suffering from borderline personality disorder (BPD) as well that found among healthy controls. Adults (N = 152, aged 18-65 years) with BPD, APD, or no psychopathology participated in a 3-week computerized diary study. We examined temporal instability in negative affect using experience-sampling methods. Both within and between days, individuals with APD showed greater affective instability compared to the healthy control individuals, although less affective instability compared to individuals with BPD. The findings are in line with affective instability (or emotional lability) as a key dimension relevant across personality disorders. Additionally, they emphasize the need for research and clinical attention to affective characteristics (alongside the more readily recognized interpersonal characteristics) of APD. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  5. Autonomous watersheds: Reducing flooding and stream erosion through real-time control

    Science.gov (United States)

    Kerkez, B.; Wong, B. P.

    2017-12-01

    We introduce an analytical toolchain, based on dynamical system theory and feedback control, to determine how many control points (valves, gates, pumps, etc.) are needed to transform urban watersheds from static to adaptive. Advances and distributed sensing and control stand to fundamentally change how we manage urban watersheds. In lieu of new and costly infrastructure, the real-time control of stormwater systems will reduce flooding, mitigate stream erosion, and improve the treatment of polluted runoff. We discuss the how open source technologies, in the form of wireless sensor nodes and remotely-controllable valves (open-storm.org), have been deployed to build "smart" stormwater systems in the Midwestern US. Unlike "static" infrastructure, which cannot readily adapt to changing inputs and land uses, these distributed control assets allow entire watersheds to be reconfigured on a storm-by-storm basis. Our results show how the control of even just a few valves within urban catchments (1-10km^2) allows for the real-time "shaping" of hydrographs, which reduces downstream erosion and flooding. We also introduce an equivalence framework that can be used by decision-makers to objectively compare investments into "smart" system to more traditional solutions, such as gray and green stormwater infrastructure.

  6. A systematic review of controlled interventions to reduce overweight and obesity for people with schizophrenia

    DEFF Research Database (Denmark)

    Hjorth, P.; Davidsen, A.S.; Killian, R.

    2014-01-01

    OBJECTIVE: Overweight and obesity are generally found among patients with schizophrenia. This may lead to serious implications for health and wellbeing. The aim was to review controlled intervention studies on reducing overweight/obesity and/or reducing physical illness in patients...... reduction and/or reducing physical illness, with standard care for patients with schizophrenia. RESULTS: All 1713 references were evaluated for inclusion in the review. Twenty-three met the inclusion criteria and were categorised into four subgroups according to tested interventions: diet, exercise...... and cognitive behavioural therapy, or mixed combinations of the three. In this review, interventions showed efficacy in reducing weight and improving physical health parameters confirming that physical health improvement was possible in patients with schizophrenia. CONCLUSION: The included studies indicate...

  7. Changing Workplaces to Reduce Work-Family Conflict: Schedule Control in a White-Collar Organization.

    Science.gov (United States)

    Kelly, Erin L; Moen, Phyllis; Tranby, Eric

    2011-04-01

    Work-family conflicts are common and consequential for employees, their families, and work organizations. Can workplaces be changed to reduce work-family conflict? Previous research has not been able to assess whether workplace policies or initiatives succeed in reducing work-family conflict or increasing work-family fit. Using longitudinal data collected from 608 employees of a white-collar organization before and after a workplace initiative was implemented, we investigate whether the initiative affects work-family conflict and fit, whether schedule control mediates these effects, and whether work demands, including long hours, moderate the initiative's effects on work-family outcomes. Analyses clearly demonstrate that the workplace initiative positively affects the work-family interface, primarily by increasing employees' schedule control. This study points to the importance of schedule control for our understanding of job quality and for management policies and practices.

  8. Topographic-driven instabilities in terrestrial bodies

    Science.gov (United States)

    Vantieghem, S.; Cebron, D.; Herreman, W.; Lacaze, L.

    2013-12-01

    Models of internal planetary fluid layers (core flows, subsurface oceans) commonly assume that these fluid envelopes have a spherical shape. This approximation however entails a serious restriction from the fluid dynamics point of view. Indeed, in the presence of mechanical forcings (precession, libration, nutation or tides) due to gravitational interaction with orbiting partners, boundary topography (e.g. of the core-mantle boundary) may excite flow instabilities and space-filling turbulence. These phenomena may affect heat transport and dissipation at the main order. Here, we focus on instabilities driven by longitudinal libration. Using a suite of theoretical tools and numerical simulations, we are able to discern a parameter range for which instability may be excited. We thereby consider deformations of different azimuthal order. This study gives the first numerical evidence of the tripolar instability. Furthermore, we explore the non-linear regime and investigate the amplitude as well as the dissipation of the saturated instability. Indeed, these two quantities control the torques on the solid layers and the thermal transport. Furthermore, based on this results, we address the issue of magnetic field generation associated with these flows (by induction or by dynamo process). This instability mechanism applies to both synchronized as non-synchronized bodies. As such, our results show that a tripolar instability might be present in various terrestrial bodies (Early Moon, Gallilean moons, asteroids, etc.), where it could participate in dynamo action. Simulation of a libration-driven tripolar instability in a deformed spherical fluid layer: snapshot of the velocity magnitude, where a complex 3D flow pattern is established.

  9. Co-simulation of heavy truck tire dynamics and electronic stability control systems (phase A).

    Science.gov (United States)

    2009-07-01

    Electronic stability control (ESC) systems have been proven to be an effective means of preventing instability and loss of control on both passenger vehicles and heavy trucks. In addition, roll stability algorithms are an effective means of reducing ...

  10. Instability and star evolution

    International Nuclear Information System (INIS)

    Mirzoyan, L.V.

    1981-01-01

    The observational data are discussed which testify that the phenomena of dynamical instability of stars and stellar systems are definite manifestations of their evolution. The study of these phenomena has shown that the instability is a regular phase of stellar evolution. It has resulted in the recognition of the most important regularities of the process of star formation concerning its nature. This became possible due to the discovery in 1947 of stellar associations in our Galaxy. The results of the study of the dynamical instability of stellar associations contradict the predictions of classical hypothesis of stellar condensation. These data supplied a basis for a new hypothesis on the formation of stars and nebulae by the decay of superdense protostars [ru

  11. Control Motion Approach of a Lower Limb Orthosis to Reduce Energy Consumption

    Directory of Open Access Journals (Sweden)

    Daniel Sanz-Merodio

    2012-12-01

    Full Text Available By analysing the dynamic principles of the human gait, an economic gait-control analysis is performed, and passive elements are included to increase the energy efficiency in the motion control of active orthoses. Traditional orthoses use position patterns from the clinical gait analyses (CGAs of healthy people, which are then de-normalized and adjusted to each user. These orthoses maintain a very rigid gait, and their energy cost is very high, reducing the autonomy of the user. First, to take advantage of the inherent dynamics of the legs, a state machine pattern with different gains in each state is applied to reduce the actuator energy consumption. Next, different passive elements, such as springs and brakes in the joints, are analysed to further reduce energy consumption. After an off-line parameter optimization and a heuristic improvement with genetic algorithms, a reduction in energy consumption of 16.8% is obtained by applying a state machine control pattern, and a reduction of 18.9% is obtained by using passive elements. Finally, by combining both strategies, a more natural gait is obtained, and energy consumption is reduced by 24.6% compared with a pure CGA pattern.

  12. Quality control of diagnostic radiology to reduce absorbed dose of patients in Iran

    International Nuclear Information System (INIS)

    Aghahadi, Bahman.

    1996-01-01

    In order to reduce absorbed dose, to increase the image quality and to reduce the numbers of rejected films various quality control parameters were applied to X ray machines. These parameter are Kilo Volt peak, Milli Ampere, Exposure Time Focal Film Distance, Inherent Filters, Additional Filters Half Value Layer, Processor Condition, Cassettes. To evaluate and to apply these parameters in diagnostic radiological centers, ten hospitals were selected and a total number of 12 X ray machines were kept under quality control program. Considering different kinds of diagnostic radiology examination and to compare the dose before and after implementation of a quality control program, two kinds of examinations include in chest and abdomen examinations were considered. For each X ray machine, ten patients and for all selected centers, 120 patients were selected for chest examination and 120 patients for abdomen examinations; before and after implementation of quality control program, a total of 480 patients were selected randomly to be controlled. Base on different examinations carried out, it was concluded that both exposure conditions and general situations in radiological centers were not acceptable. The dosimetry results show that the average ski dose for chest and abdomen examinations were 0.28 m Gy and 4.23 Gy respectively. Before implementation of quality control step to reduce the surface skin dose, quality control parameters were applied and the exposure conditions were imposed. On average the absorbed doses for chest and abdomen examination were decreased to 79% and 61% respectively after the implementation of the program. From dose reduction point of view, the results of a part of this project which made by co-operation of International Atomic Energy Agency showed that Iran acquired the first grade for chest examination and second grade for abdomen examination. Base on the results obtained, the number of patients under chest and abdomen examination were 4041588 and

  13. Using trap crops for control of Acalymma vittatum (Coleoptera: Chrysomelidae) reduces insecticide use in butternut squash.

    Science.gov (United States)

    Cavanagh, A; Hazzard, R; Adler, L S; Boucher, J

    2009-06-01

    Striped cucumber beetle, Acalymma vittatum F., is the primary insect pest of cucurbit crops in the northeastern United States. Adult beetles colonize squash crops from field borders, causing feeding damage at the seedling stage and transmitting bacterial wilt Erwinia tracheiphila Hauben et al. 1999. Conventional control methods rely on insecticide applications to the entire field, but surrounding main crops with a more attractive perimeter could reduce reliance on insecticides. A. cittatum shows a marked preference for Blue Hubbard squash (Cucurbita maxima Duchesne) over butternut squash (C. moschata Poir). Given this preference, Blue Hubbard squash has the potential to be an effective perimeter trap crop. We evaluated this system in commercial butternut fields in 2003 and 2004, comparing fields using perimeter trap cropping with Blue Hubbard to conventionally managed fields. In 2003, we used a foliar insecticide to control beetles in the trap crop borders, and in 2004, we compared systemic and foliar insecticide treatments for the trap crop borders. We found that using a trap crop system reduced or eliminated the need to spray the main crop area, reducing insecticide use by up to 94% compared with conventional control methods, with no increase in herbivory or beetle numbers. We surveyed the growers who participated in these experiments and found a high level of satisfaction with the effectiveness and simplicity of the system. These results suggest that this method of pest control is both effective and simple enough in its implementation to have high potential for adoption among growers.

  14. Causes of genome instability

    DEFF Research Database (Denmark)

    Langie, Sabine A S; Koppen, Gudrun; Desaulniers, Daniel

    2015-01-01

    function, chromosome segregation, telomere length). The purpose of this review is to describe the crucial aspects of genome instability, to outline the ways in which environmental chemicals can affect this cancer hallmark and to identify candidate chemicals for further study. The overall aim is to make......Genome instability is a prerequisite for the development of cancer. It occurs when genome maintenance systems fail to safeguard the genome's integrity, whether as a consequence of inherited defects or induced via exposure to environmental agents (chemicals, biological agents and radiation). Thus...

  15. Instabilities and nonequilibrium structures

    International Nuclear Information System (INIS)

    Tirapegui, E.; Villarroel, D.

    1987-01-01

    Physical systems can be studied both near to and far from equilibrium where instabilities appear. The behaviour in these two regions is reviewed in this book, from both the theoretical and application points of view. The influence of noise in these situations is an essential feature which cannot be ignored. It is therefore discussed using phenomenological and theoretical approaches for the numerous problems which still remain in the field. This volume should appeal to mathematicians and physicists interested in the areas of instability, bifurcation theory, dynamical systems, pattern formation, nonequilibrium structures and statistical mechanics. (Auth.)

  16. RINGED ACCRETION DISKS: INSTABILITIES

    Energy Technology Data Exchange (ETDEWEB)

    Pugliese, D.; Stuchlík, Z., E-mail: d.pugliese.physics@gmail.com, E-mail: zdenek.stuchlik@physics.cz [Institute of Physics and Research Centre of Theoretical Physics and Astrophysics, Faculty of Philosophy and Science, Silesian University in Opava, Bezručovo náměstí 13, CZ-74601 Opava (Czech Republic)

    2016-04-01

    We analyze the possibility that several instability points may be formed, due to the Paczyński mechanism of violation of mechanical equilibrium, in the orbiting matter around a supermassive Kerr black hole. We consider a recently proposed model of a ringed accretion disk, made up by several tori (rings) that can be corotating or counter-rotating relative to the Kerr attractor due to the history of the accretion process. Each torus is governed by the general relativistic hydrodynamic Boyer condition of equilibrium configurations of rotating perfect fluids. We prove that the number of the instability points is generally limited and depends on the dimensionless spin of the rotating attractor.

  17. Active Lubrication for Reducing Wear and Vibration: A combination of Fluid Power Control and Tribology

    DEFF Research Database (Denmark)

    Nicoletti, Rodrigo; Santos, Ilmar

    2002-01-01

    The use of fluid power to reduce and control rotor vibration in rotating machines is investigated. An active hybrid bearing is studied, whose main objective is to reduce wear and vibration between rotating and stationary machinery parts. By injecting pressurised oil into the oil film, through...... orifices machined in the bearing pads, one can alter the machine dynamic characteristics, thus enhancing its operational range. A mathematical model of the rotor-bearing system, as well as of the hydraulic system, is presented. Numerical results of the system frequency response show good agreement...

  18. Changes of NSSS control system setpoint for operation at reduced temperature at YGN 3 and 4

    International Nuclear Information System (INIS)

    Song, I. H.; Son, S. H.; Lee, K. C.; Son, J. J.; Seo, J. T.; Lee, S. H.; Park, W. K.; Hwang, H. C.; Lee, J. H.

    2003-01-01

    The differences of the design operational conditions and best estimate operational conditions, which were expected to be conditions during the plant operation, during the application of operation at reduced temperature at YGN 3 and 4 are larger than those during the construction period. Therefore, each sets of NSSS control system setpoints were generated for ORT design operational condition and for ORT best estimate operational condition. The analytical results shows that the plant performance requirements are satisfied by changing the NSSS control system setpoints for each operational conditions. The NSSS control system setpoints were changed after power operation after application of the ORT due to unexpected mismatch of plant conditions from the best estimate operational conditions. The plant conditions are needed to be monitored cycle by cycle for the detection of such conditions which requires the changing of the NSSS control system

  19. Early rigorous control interventions can largely reduce dengue outbreak magnitude: experience from Chaozhou, China.

    Science.gov (United States)

    Liu, Tao; Zhu, Guanghu; He, Jianfeng; Song, Tie; Zhang, Meng; Lin, Hualiang; Xiao, Jianpeng; Zeng, Weilin; Li, Xing; Li, Zhihao; Xie, Runsheng; Zhong, Haojie; Wu, Xiaocheng; Hu, Wenbiao; Zhang, Yonghui; Ma, Wenjun

    2017-08-02

    Dengue fever is a severe public heath challenge in south China. A dengue outbreak was reported in Chaozhou city, China in 2015. Intensified interventions were implemented by the government to control the epidemic. However, it is still unknown the degree to which intensified control measures reduced the size of the epidemics, and when should such measures be initiated to reduce the risk of large dengue outbreaks developing? We selected Xiangqiao district as study setting because the majority of the indigenous cases (90.6%) in Chaozhou city were from this district. The numbers of daily indigenous dengue cases in 2015 were collected through the national infectious diseases and vectors surveillance system, and daily Breteau Index (BI) data were reported by local public health department. We used a compartmental dynamic SEIR (Susceptible, Exposed, Infected and Removed) model to assess the effectiveness of control interventions, and evaluate the control effect of intervention timing on dengue epidemic. A total of 1250 indigenous dengue cases was reported from Xiangqiao district. The results of SEIR modeling using BI as an indicator of actual control interventions showed a total of 1255 dengue cases, which is close to the reported number (n = 1250). The size and duration of the outbreak were highly sensitive to the intensity and timing of interventions. The more rigorous and earlier the control interventions implemented, the more effective it yielded. Even if the interventions were initiated several weeks after the onset of the dengue outbreak, the interventions were shown to greatly impact the prevalence and duration of dengue outbreak. This study suggests that early implementation of rigorous dengue interventions can effectively reduce the epidemic size and shorten the epidemic duration.

  20. Reduced Risk of Barrett's Esophagus in Statin Users: Case-Control Study and Meta-Analysis.

    Science.gov (United States)

    Beales, Ian L P; Dearman, Leanne; Vardi, Inna; Loke, Yoon

    2016-01-01

    Use of statins has been associated with a reduced incidence of esophageal adenocarcinoma in population-based studies. However there are few studies examining statin use and the development of Barrett's esophagus. The purpose of this study was to examine the association between statin use and the presence of Barrett's esophagus in patients having their first gastroscopy. We have performed a case-control study comparing statin use between patients with, and without, an incident diagnosis of non-dysplastic Barrett's esophagus. Male Barrett's cases (134) were compared to 268 male age-matched controls in each of two control groups (erosive gastro-esophageal reflux and dyspepsia without significant upper gastrointestinal disease). Risk factor and drug exposure were established using standardised interviews. Logistic regression was used to compare statin exposure and correct for confounding factors. We performed a meta-analysis pooling our results with three other case-control studies. Regular statin use was associated with a significantly lower incidence of Barrett's esophagus compared to the combined control groups [adjusted OR 0.62 (95 % confidence intervals 0.37-0.93)]. This effect was more marked in combined statin plus aspirin users [adjusted OR 0.43 (95 % CI 0.21-0.89)]. The inverse association between statin or statin plus aspirin use and risk of Barrett's was significantly greater with longer duration of use. Meta-analysis of pooled data (1098 Barrett's, 2085 controls) showed that statin use was significantly associated with a reduced risk of Barrett's esophagus [pooled adjusted OR 0.63 (95 % CI 0.51-0.77)]. Statin use is associated with a reduced incidence of a new diagnosis of Barrett's esophagus.

  1. Early rigorous control interventions can largely reduce dengue outbreak magnitude: experience from Chaozhou, China

    Directory of Open Access Journals (Sweden)

    Tao Liu

    2017-08-01

    Full Text Available Abstract Background Dengue fever is a severe public heath challenge in south China. A dengue outbreak was reported in Chaozhou city, China in 2015. Intensified interventions were implemented by the government to control the epidemic. However, it is still unknown the degree to which intensified control measures reduced the size of the epidemics, and when should such measures be initiated to reduce the risk of large dengue outbreaks developing? Methods We selected Xiangqiao district as study setting because the majority of the indigenous cases (90.6% in Chaozhou city were from this district. The numbers of daily indigenous dengue cases in 2015 were collected through the national infectious diseases and vectors surveillance system, and daily Breteau Index (BI data were reported by local public health department. We used a compartmental dynamic SEIR (Susceptible, Exposed, Infected and Removed model to assess the effectiveness of control interventions, and evaluate the control effect of intervention timing on dengue epidemic. Results A total of 1250 indigenous dengue cases was reported from Xiangqiao district. The results of SEIR modeling using BI as an indicator of actual control interventions showed a total of 1255 dengue cases, which is close to the reported number (n = 1250. The size and duration of the outbreak were highly sensitive to the intensity and timing of interventions. The more rigorous and earlier the control interventions implemented, the more effective it yielded. Even if the interventions were initiated several weeks after the onset of the dengue outbreak, the interventions were shown to greatly impact the prevalence and duration of dengue outbreak. Conclusions This study suggests that early implementation of rigorous dengue interventions can effectively reduce the epidemic size and shorten the epidemic duration.

  2. Ecological feedbacks can reduce population-level efficacy of wildlife fertility control

    Science.gov (United States)

    Ransom, Jason I.; Powers, Jenny G.; Hobbs, N. Thompson; Baker, Dan L.

    2014-01-01

    1. Anthropogenic stress on natural systems, particularly the fragmentation of landscapes and the extirpation of predators from food webs, has intensified the need to regulate abundance of wildlife populations with management. Controlling population growth using fertility control has been considered for almost four decades, but nearly all research has focused on understanding effects of fertility control agents on individual animals. Questions about the efficacy of fertility control as a way to control populations remain largely unanswered. 2. Collateral consequences of contraception can produce unexpected changes in birth rates, survival, immigration and emigration that may reduce the effectiveness of regulating animal abundance. The magnitude and frequency of such effects vary with species-specific social and reproductive systems, as well as connectivity of populations. Developing models that incorporate static demographic parameters from populations not controlled by contraception may bias predictions of fertility control efficacy. 3. Many population-level studies demonstrate that changes in survival and immigration induced by fertility control can compensate for the reduction in births caused by contraception. The most successful cases of regulating populations using fertility control come from applications of contraceptives to small, closed populations of gregarious and easily accessed species. 4. Fertility control can result in artificial selection pressures on the population and may lead to long-term unintentional genetic consequences. The magnitude of such selection is dependent on individual heritability and behavioural traits, as well as environmental variation. 5. Synthesis and applications. Understanding species' life-history strategies, biology, behavioural ecology and ecological context is critical to developing realistic expectations of regulating populations using fertility control. Before time, effort and funding are invested in wildlife

  3. Early Prevention Method for Power Systems Instability

    DEFF Research Database (Denmark)

    Dmitrova, Evgenia

    containing no voltage sources). The main functionality of the early prevention method is to deliver control solution allowing escape from instability on the basis of data obtained by PMU measurements. The developed algorithm performs identification of the optimal node for countermeasure application...... instability was created. Utilizing synthetic PMU data, the early prevention method proposed a location and an amount of the countermeasure which will prevent instability; the prediction of the resulting stability margins corresponding to application of the suggested countermeasure was carried out....... The predicted effect of the suggested countermeasure application is in a good agreement with the results obtained by RMS dynamic simulation. Developed method enables adaptive preventive control for near real-time stability maintenance. The achieved results are opening promising perspective for power system...

  4. Buneman instability and Pierce instability in a collisionless bounded plasma

    International Nuclear Information System (INIS)

    Iizuka, Satoru; Saeki, Koichi; Sato, Noriyoshi; Hatta, Yoshisuke

    1983-01-01

    A systematic experiment is performed on the Buneman instability and the Pierce instability in a bounded plasma consisting of beam electrons and stationary ions. Current fluctuations are confirmed to be induced by the Buneman instability. On the other hand, the Pierce instability gives rise to a current limitation. The phenomena are well explained by Mikhailovskii's theory taking account of ion motion in a bounded plasma. (author)

  5. Reducing the energy consumption of an earth–air heat exchanger with a PID control system

    International Nuclear Information System (INIS)

    Diaz-Mendez, S.E.; Patiño-Carachure, C.; Herrera-Castillo, J.A.

    2014-01-01

    Highlights: • The application of control actions to green technologies has been simulated. • Energy consumption of green technologies can be reduced even more. • The efficiency of green technologies can be raised. • Environmental concerns can be diminished. • The sustainability of the planet can be increased. - Abstract: Reducing environmental emissions is one of the challenges that human being has to overcome. It can only be reached with a proper energetic efficiency and management of the processes that exist in the society nowadays. Several academic works have mentioned that raising the efficiency of a process it also increases sustainability and in turn decreases the environmental impact. One process that requires much attention is the cooling and heating of buildings; this process contributes to the major part of the electric bill, in particular, if a conventional and old air conditioning is used as commonly occurs in many countries. In recent years there have been developed new alternatives that are used in few countries, such as the earth–air heat exchanger, where air is passed through a heat exchanger buried a few meters below the ground. The heat exchanger takes advantage of the well-known difference between the temperature of the surrounding air and the temperature of the ground for cooling or heating the air that is subsequently injected into the buildings. This process requires less energy, then in the present work is thought that a PID (Proportional, Integral and Derivative) controller can be applied to an earth–air heat exchanger to reduce even more the energy consumption. Therefore, a simulation of a thermodynamic model of an earth–air heat exchanger was done and used along with a PID controller, to estimate savings in energy consumption. The results show that the energy consumption can be reduced up to 87% with the PID control, hence the efficiency of the process is increased as well as the sustainability of the planet and thus the

  6. A Reduced Switch Voltage Stress Class E Power Amplifier Using Harmonic Control Network

    OpenAIRE

    Ali Reza Zirak; Sobhan Roshani

    2016-01-01

    In this paper, a harmonic control network (HCN) is presented to reduce the voltage stress (maximum MOSFET voltage) of the class E power amplifier (PA). Effects of the HCN on the amplifier specifications are investigated. The results show that the proposed HCN affects several specifications of the amplifier, such as drain voltage, switch current, output power capability (Cp factor), and drain impedance. The output power capability of the presented amplifier is also improved, compared with the ...

  7. Effectiveness of comprehensive tobacco control programmes in reducing teenage smoking in the USA

    OpenAIRE

    Wakefield, M.; Chaloupka, F.

    2000-01-01

    OBJECTIVE—To describe the extent to which comprehensive statewide tobacco control programmes in the USA have made progress toward reducing teenage smoking.
DATA SOURCES—Literature search of Medline for reviews of effectiveness of programme and policy elements, plus journal articles and personal request for copies of publicly released reports and working papers from evaluation staff in each of the state programmes of California, Massachusetts, Arizona, Oregon, and Florida.
STUDY SELECTION—All ...

  8. A fast beam-ion instability

    Energy Technology Data Exchange (ETDEWEB)

    Stupakov, G V [Stanford Linear Accelerator Center, Menlo Park, CA (United States)

    1996-08-01

    The ionization of residual gas by an electron beam in an accelerator generates ions that can resonantly couple to the beam through a wave propagating in the beam-ion system. Results of the study of a beam-ion instability are presented for a multi-bunch train taking into account the decoherence of ion oscillations due to the ion frequency spread and spatial variation of the ion frequency. It is shown that the combination of both effects can substantially reduce the growth rate of the instability. (author)

  9. Controllable synthesis of palladium nanocubes/reduced graphene oxide composites and their enhanced electrocatalytic performance

    Science.gov (United States)

    Zhang, Yuting; Huang, Qiwei; Chang, Gang; Zhang, Zaoli; Xia, Tiantian; Shu, Honghui; He, Yunbin

    2015-04-01

    Homogeneous distribution of cube-shaped Pd nanocrystals on the surface of reduced graphene oxide is obtained via a facile one-step method by employing AA and KBr as the reductant and capping agent, respectively. The experimental factors affecting the morphology and structure of Pd nanoparticles have been systematically investigated to explore the formation mechanism of Pd nanocubes (PdNCs). It is revealed that PdNCs enclosed by active {100} facets with an average side length of 15 nm were successfully synthesized on the surface of reduced graphene oxide. KBr plays the role for facet selection by surface passivation and AA controls the reduction speed of Pd precursors, both of which govern the morphology changes of palladium nanoparticles. In the further electrochemical evaluations, the Pd nanocubes/reduced graphene oxide composites show better electrocatalytic activity and stability towards the electro-oxidation of ethanol than both reduced graphene oxide supported Pd nanoparticles and free-standing PdNCs. It could be attributed to the high electrocatalytic activity of the dominated active {100} crystal facets of Pd nanocubes and the enhanced electron transfer of graphene. The developed approach provide a versatile way for shape-controlled preparation of noble metal nanoparticles, which can work as novel electrocatalysts in the application of direct alcohols fuel cells.

  10. Elbow joint instability

    DEFF Research Database (Denmark)

    Olsen, Bo Sanderhoff; Henriksen, M G; Søjbjerg, Jens Ole

    1994-01-01

    The effect of simultaneous ulnar and radial collateral ligament division on the kinematics of the elbow joint is studied in a cadaveric model. Severance of the anterior part of the ulnar collateral ligament and the annular ligament led to significant elbow joint instability in valgus and varus...

  11. Structural and Material Instability

    DEFF Research Database (Denmark)

    Cifuentes, Gustavo Cifuentes

    This work is a small contribution to the general problem of structural and material instability. In this work, the main subject is the analysis of cracking and failure of structural elements made from quasi-brittle materials like concrete. The analysis is made using the finite element method. Three...

  12. Agricultural Markets Instability

    NARCIS (Netherlands)

    Garrido, A.; Brümmer, B.; M'Barek, R.; Gielen-Meuwissen, M.P.M.; Morales-Opazo, C.

    2016-01-01

    Since the financial and food price crises of 2007, market instability has been a topic of major concern to agricultural economists and policy professionals. This volume provides an overview of the key issues surrounding food prices volatility, focusing primarily on drivers, long-term implications of

  13. Comment on critical instability

    International Nuclear Information System (INIS)

    King, S.F.; Suzuki, Mahiko

    1992-01-01

    We discuss the problem of the mass splitting between top and bottom quarks, within the context of Nambu-Jona-Lasinio type models involving top and bottom quark condensates. We interpret the phenomenon of 'critical instability' recently proposed to account for such a mass splitting as the fine-tuning of two vacuum expectation values in a composite two-Higgs doublet model. (orig.)

  14. Cognitive control of familiarity: directed forgetting reduces proactive interference in working memory.

    Science.gov (United States)

    Festini, Sara B; Reuter-Lorenz, Patricia A

    2014-03-01

    Proactive interference (PI) occurs when previously learned information interferes with new learning. In a working memory task, PI induces longer response times and more errors to recent negative probes than to new probes, presumably because the recent probe's familiarity invites a "yes" response. Warnings, longer intertrial intervals, and the increased contextual salience of the probes can reduce but not eliminate PI, suggesting that cognitive control over PI is limited. Here we tested whether control exerted in the form of intentional forgetting performed during working memory can reduce the magnitude of PI. In two experiments, participants performed a working memory task with directed-forgetting instructions and the occasional presentation of recent probes. Surprise long-term memory testing indicated better memory for to-be-remembered than for to-be-forgotten items, documenting the classic directed-forgetting effect. Critically, in working memory, PI was virtually eliminated for recent probes from prior to-be-forgotten lists, as compared to recent probes from prior to-be-remembered lists. Thus cognitive control, when executed via directed forgetting, can reduce the adverse and otherwise persistent interference from familiarity, an effect that we attribute to attenuated memory representations of the to-be-forgotten items.

  15. Controlling spark timing for consecutive cycles to reduce the cyclic variations of SI engines

    International Nuclear Information System (INIS)

    Kaleli, Alirıza; Ceviz, Mehmet Akif; Erenturk, Köksal

    2015-01-01

    Minimization of the cyclic variations is one of the most important design goal for spark-ignited engines. Primary motivation of this study is to reduce the cyclic variations in spark ignition engines by controlling the spark timing for consecutive cycles. A stochastic model was performed between spark timing and in–cylinder maximum pressure by using the system identification techniques. The incylinder maximum pressure of the next cycle was predicted with this model. Minimum variance and generalized minimum variance controllers were designed to regulate the in–cylinder maximum pressure by changing the spark timing for consecutive cycles of the test engine. The produced control algorithms were built in LabView environment and installed to the Field Programmable Gate Arrays (FPGA) chassis. According to the test results, the in–cylinder maximum pressure of the next pressure cycle can be predicted fairly well, and the spark timing can be regulated to keep the in–cylinder maximum pressure in a desired band to reduce the cyclic variations. At fixed spark timing experiments, the COV Pmax and COV imep were 3.764 and 0.677%, whereas they decreased to 3.208 and 0.533% when GMV controller was applied, respectively. - Highlights: • Cycle per cycle spark timing control was carried out. • A stochastic process model was described between P max and the spark timing. • The cyclic variations in P max was decreased by keeping it in a desired band. • Different controllers were used to adjust spark timing signal of the next cycle. • COV Pmax was decreased by about 15% by using GMV controller

  16. Control of asthma for reducing the risk of bronchospasm in asthmatics undergoing general anesthesia and/or intravascular administration of radiographic contrast media.

    Science.gov (United States)

    Liccardi, Gennaro; Salzillo, Antonello; De Blasio, Francesco; D'Amato, Gennaro

    2009-07-01

    It is well known that patients suffering from bronchial asthma undergoing surgical procedures requiring general anesthesia (GA) or the administration of water soluble radiographic contrast media (RCM) have an increased risk of potentially severe bronchospasm. Nevertheless, little attention has been devoted to the possible preventive measures to reduce the occurrence of this potentially life-threatening event. It has been shown that the most important risk factor for bronchospasm during GA induction and/or the use of RCM is represented by a high degree of bronchial hyperreactivity with airway instability not adequately controlled by long-term anti-inflammatory treatment. The aim of this commentary is to underline the need for an accurate clinical and functional evaluation of asthmatics undergoing surgical procedures requiring GA or radiological procedures requiring the administration of RCM, as well as to suggest a stepwise preventive pharmacological approach for reducing the risk of bronchospasm. The authors' suggestions represent clinical experience of the respiratory section of an internal hospital-based working group whose aim is the prevention of asthmatic/anaphylactic/anaphylactoid reactions during the administration of anesthetics and/or RCM. The MEDLINE database was searched with a combination of keywords: general anesthesia, radio contrast media [and] bronchial asthma. The main limitation of this commentary is the scarcity of available literature on this topic. The authors suggest a therapeutic approach before surgical procedures requiring GA and/or RCM administration based on the degree of asthma control as assessed by clinical/functional criteria. In this setting, in addition to the necessity of obtaining the best control of airway reactivity, the authors suggest that an optimal control of asthma symptoms in 'real life' conditions might likely constitute a safety issue in asthmatic patients in the case of emergency procedures.

  17. Tracking Code for Microwave Instability

    International Nuclear Information System (INIS)

    Heifets, S.; SLAC

    2006-01-01

    To study microwave instability the tracking code is developed. For bench marking, results are compared with Oide-Yokoya results [1] for broad-band Q = 1 impedance. Results hint to two possible mechanisms determining the threshold of instability

  18. Instabilities in thin tunnel junctions

    International Nuclear Information System (INIS)

    Konkin, M.K.; Adler, J.G.

    1978-01-01

    Tunnel junctions prepared for inelastic electron tunneling spectroscopy are often plagued by instabilities in the 0-500-meV range. This paper relates the bias at which the instability occurs to the barrier thickness

  19. Linear study of the precessional fishbone instability

    Science.gov (United States)

    Idouakass, M.; Faganello, M.; Berk, H. L.; Garbet, X.; Benkadda, S.

    2016-10-01

    The precessional fishbone instability is an m = n = 1 internal kink mode destabilized by a population of trapped energetic particles. The linear phase of this instability is studied here, analytically and numerically, with a simplified model. This model uses the reduced magneto-hydrodynamics equations for the bulk plasma and the Vlasov equation for a population of energetic particles with a radially decreasing density. A threshold condition for the instability is found, as well as a linear growth rate and frequency. It is shown that the mode frequency is given by the precession frequency of the deeply trapped energetic particles at the position of strongest radial gradient. The growth rate is shown to scale with the energetic particle density and particle energy while it is decreased by continuum damping.

  20. Mirror Instability in the Turbulent Solar Wind

    Energy Technology Data Exchange (ETDEWEB)

    Hellinger, Petr [Astronomical Institute, CAS, Bocni II/1401,CZ-14100 Prague (Czech Republic); Landi, Simone; Verdini, Andrea; Franci, Luca [Dipartimento di Fisica e Astronomia, Università degli Studi di Firenze Largo E. Fermi 2, I-50125 Firenze (Italy); Matteini, Lorenzo, E-mail: petr.hellinger@asu.cas.cz [Department of Physics, Imperial College London, London SW7 2AZ (United Kingdom)

    2017-04-01

    The relationship between a decaying strong turbulence and the mirror instability in a slowly expanding plasma is investigated using two-dimensional hybrid expanding box simulations. We impose an initial ambient magnetic field perpendicular to the simulation box, and we start with a spectrum of large-scale, linearly polarized, random-phase Alfvénic fluctuations that have energy equipartition between kinetic and magnetic fluctuations and a vanishing correlation between the two fields. A turbulent cascade rapidly develops, magnetic field fluctuations exhibit a Kolmogorov-like power-law spectrum at large scales and a steeper spectrum at sub-ion scales. The imposed expansion (taking a strictly transverse ambient magnetic field) leads to the generation of an important perpendicular proton temperature anisotropy that eventually drives the mirror instability. This instability generates large-amplitude, nonpropagating, compressible, pressure-balanced magnetic structures in a form of magnetic enhancements/humps that reduce the perpendicular temperature anisotropy.

  1. Anomalous plasma transport due to electron temperature gradient instability

    International Nuclear Information System (INIS)

    Tokuda, Sinji; Ito, Hiroshi; Kamimura, Tetsuo.

    1979-01-01

    The collisionless drift wave instability driven by an electron temperature inhomogeneity (electron temperature gradient instability) and the enhanced transport processes associated with it are studied using a two-and-a-half dimensional particle simulation code. The simulation results show that quasilinear diffusion in phase space is an important mechanism for the saturation of the electron temperature gradient instability. Also, the instability yields particle fluxes toward the hot plasma regions. The heat conductivity of the electron temperature perpendicular to the magnetic field, T sub(e'), is not reduced by magnetic shear but remains high, whereas the heat conductivity of the parallel temperature, T sub(e''), is effectively reduced, and the instability stabilized. (author)

  2. The Effect of 2 Forms of Talocrural Joint Traction on Dorsiflexion Range of Motion and Postural Control in Those With Chronic Ankle Instability.

    Science.gov (United States)

    Powden, Cameron J; Hogan, Kathleen K; Wikstrom, Erik A; Hoch, Matthew C

    2017-05-01

    Talocrural joint mobilizations are commonly used to address deficits associated with chronic ankle instability (CAI). Examine the immediate effects of talocrural joint traction in those with CAI. Blinded, crossover. Laboratory. Twenty adults (14 females; age = 23.80 ± 4.02 y; height = 169.55 ± 12.38 cm; weight = 78.34 ± 16.32 kg) with self-reported CAI participated. Inclusion criteria consisted of a history of ≥1 ankle sprain, ≥2 episodes of giving way in the previous 3 mo, answering "yes" to ≥4 questions on the Ankle Instability Instrument, and ≤24 on the Cumberland Ankle Instability Tool. Subjects participated in 3 sessions in which they received a single treatment session of sustained traction (ST), oscillatory traction (OT), or a sham condition in a randomized order. Interventions consisted of four 30-s sets of traction with 1 min of rest between sets. During ST and OT, the talus was distracted distally from the ankle mortise to the end-range of accessory motion. ST consisted of continuous distraction and OT involved 1-s oscillations between the mid and end-range of accessory motion. The sham condition consisted of physical contact without force application. Preintervention and postintervention measurements of weight-bearing dorsiflexion, dynamic balance, and static single-limb balance were collected. The independent variable was treatment (ST, OT, sham). The dependent variables included pre-to-posttreatment change scores for the WBLT (cm), normalized SEBTAR (%), and time-to-boundary (TTB) variables(s). Separate 1-way ANOVAs examined differences between treatments for each dependent variable. Alpha was set a priori at P manual therapies.

  3. A randomized controlled trial of mindfulness to reduce stress and burnout among intern medical practitioners.

    Science.gov (United States)

    Ireland, Michael J; Clough, Bonnie; Gill, Kim; Langan, Fleur; O'Connor, Angela; Spencer, Lyndall

    2017-04-01

    Stress and burnout are highly prevalent among medical doctors, and are associated with negative consequences for doctors, patients, and organizations. The purpose of the current study was to examine the effectiveness of a mindfulness training intervention in reducing stress and burnout among medical practitioners, by means of a Randomised Controlled Trial design. Participants were 44 intern doctors completing an emergency department rotation in a major Australian hospital. Participants were randomly assigned to either an active control (one hour extra break per week) or the 10-week mindfulness training intervention. Measures of stress and burnout were taken pre-, mid- and post intervention. Participants undergoing the 10-week mindfulness training program reported greater improvements in stress and burnout relative to participants in the control condition. Significant reduction in stress and burnout was observed for participants in the mindfulness condition. No such reductions were observed for participants in the control condition. Mindfulness interventions may provide medical practitioners with skills to effectively manage stress and burnout, thereby reducing their experience of these symptoms. It is likely that doctors would benefit from the inclusion of such a training program as a part of their general medical education.

  4. The efficacy of gum chewing in reducing postoperative ileus: a multisite randomized controlled trial.

    Science.gov (United States)

    Forrester, David Anthony Tony; Doyle-Munoz, Janet; McTigue, Toni; D'Andrea, Stephanie; Natale-Ryan, Angela

    2014-01-01

    The purpose of this prospective, attention-controlled, randomized study was to determine whether postoperative gum chewing reduces the duration of postoperative ileus symptoms following elective open or laparoscopic sigmoid colectomy when compared with standard care or an attention-control intervention. Forty-seven subjects scheduled for either an open or laparoscopic colon resection participated in the study. Subjects were recruited preoperatively at the preadmission learning centers of the 2 acute care medical centers that comprised the study settings. Subjects were randomized to 3 groups: (1) standard postoperative care (n = 18); (2) standard care and a silicone-adhesive patch applied to the deltoid region of the upper arm as an attention control (n = 16); and (3) standard care and gum chewing (n = 13). Standard postoperative care included removal of the nasogastric tube, early ambulation, nothing by mouth with ice chips only until the first passage of flatus, and then advancement of diet until tolerance of solid food. No statistically significant differences were found among the 3 study groups for the 4 postoperative outcome variables measured: (1) first passage of flatus; (2) first bowel movement; (3) return of hunger; and (4) ability to tolerate solid food for one meal. Postoperative gum chewing was not found to be more effective than standard postoperative care or our attention-control intervention in reducing the duration of postoperative ileus symptoms, length of stay, or complications among patients following open/laparoscopic sigmoid colectomy.

  5. Controlled synthesis of concave tetrahedral palladium nanocrystals by reducing Pd(acac)2 with carbon monoxide

    International Nuclear Information System (INIS)

    Zhu, Hai; Chi, Quan; Zhao, Yanxi; Li, Chunya; Tang, Heqing; Li, Jinlin; Huang, Tao; Liu, Hanfan

    2012-01-01

    Graphical abstract: By using CO as a reducing agent, uniform and well-defined concave tetrahedral Pd nanocrystals were successfully synthesized. CO flow rate was the most essential for the formation of the concave tetrahedral nanostructures. The morphologies and sizes of the final products can be well controlled by adjusting the flow rate of CO. Highlights: ► By using CO as a reducing agent, concave tetrahedral Pd nanocrystals were obtained. ► CO flow rate is critical to the formation of concave tetrahedral Pd nanocrystals. ► The selective adsorption of CO on (1 1 0) facets is essential to concave Pd tetrahedra. -- Abstract: CO reducing strategy to control the morphologies of palladium nanocrystals was investigated. By using CO as a reducing agent, uniform and well-defined concave tetrahedral Pd nanocrystals with a mean size of about 55 ± 2 nm were readily synthesized with Pd(acac) 2 as a precursor and PVP as a stabilizer. The structures of the as-prepared Pd nanocrystals were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), ultraviolet–visible (UV–vis) absorption spectroscopy and electrochemical measurements. The results demonstrated that CO was the most essential for the formation of the concave tetrahedral Pd nanostructures. The morphologies and sizes of the final products can be well controlled by adjusting the flow rate of CO. The most appropriate CO flow rate, temperature and time for the formation of the ideal concave tetrahedral Pd nanocrystals was 0.033 mL s −1 , 100 °C and 3 h, respectively.

  6. Can Tobacco Control Be Transformative? Reducing Gender Inequity and Tobacco Use among Vulnerable Populations

    Science.gov (United States)

    Greaves, Lorraine

    2014-01-01

    Tobacco use and exposure is unequally distributed across populations and countries and among women and men. These trends and patterns reflect and cause gender and economic inequities along with negative health impacts. Despite a commitment to gender analysis in the preamble to Framework Convention on Tobacco Control there is much yet to be done to fully understand how gender operates in tobacco control. Policies, program and research in tobacco control need to not only integrate gender, but rather operationalize gender with the goal of transforming gender and social inequities in the course of tobacco control initiatives. Gender transformative tobacco control goes beyond gender sensitive efforts and challenges policy and program developers to apply gender theory in designing their initiatives, with the goal of changing negative gender and social norms and improving social, economic, health and social indicators along with tobacco reduction. This paper outlines what is needed to progress tobacco control in enhancing the status of gendered and vulnerable groups, with a view to reducing gender and social inequities due to tobacco use and exposure. PMID:24402065

  7. Autogenic training to reduce anxiety in nursing students: randomized controlled trial.

    Science.gov (United States)

    Kanji, Nasim; White, Adrian; Ernst, Edzard

    2006-03-01

    This paper reports a study to determine the effectiveness of autogenic training in reducing anxiety in nursing students. Nursing is stressful, and nursing students also have the additional pressures and uncertainties shared with all academic students. Autogenic training is a relaxation technique consisting of six mental exercises and is aimed at relieving tension, anger and stress. Meta-analysis has found large effect sizes for autogenic trainings intervention comparisons, medium effect sizes against control groups, and no effects when compared with other psychological therapies. A controlled trial with 50 nursing students found that the number of certified days off sick was reduced by autogenic training compared with no treatment, and a second trial with only 18 students reported greater improvement in Trait Anxiety, but not State Anxiety, compared with untreated controls. A randomized controlled trial with three parallel arms was completed in 1998 with 93 nursing students aged 19-49 years. The setting was a university college in the United Kingdom. The treatment group received eight weekly sessions of autogenic training, the attention control group received eight weekly sessions of laughter therapy, and the time control group received no intervention. The outcome measures were the State-Trait Anxiety Inventory, the Maslach Burnout Inventory, blood pressure and pulse rate completed at baseline, 2 months (end of treatment), and 5, 8, and 11 months from randomization. There was a statistically significantly greater reduction of State (Pautogenic training group than in both other groups immediately after treatment. There were no differences between the groups for the Maslach Burnout Inventory. The autogenic training group also showed statistically significantly greater reduction immediately after treatment in systolic (PAutogenic training has at least a short-term effect in alleviating stress in nursing students.

  8. Evaluation of nitrogen containing reducing agents for the corrosion control of materials relevant to nuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Padma S. [Water and Steam Chemistry Division, BARC Facilities, Kalpakkam, Tamilnadu (India); Mohan, D. [Department of Chemistry, Anna University, Chennai, Tamilnadu (India); Chandran, Sinu; Rajesh, Puspalata; Rangarajan, S. [Water and Steam Chemistry Division, BARC Facilities, Kalpakkam, Tamilnadu (India); Velmurugan, S., E-mail: svelu@igcar.gov.in [Water and Steam Chemistry Division, BARC Facilities, Kalpakkam, Tamilnadu (India)

    2017-02-01

    Materials undergo enhanced corrosion in the presence of oxidants in aqueous media. Usually, hydrogen gas or water soluble reducing agents are used for inhibiting corrosion. In the present study, the feasibility of using alternate reducing agents such as hydrazine, aqueous ammonia, and hydroxylamine that can stay in the liquid phase was investigated. A comparative study of corrosion behavior of the structural materials of the nuclear reactor viz. carbon steel (CS), stainless steel (SS-304 LN), monel-400 and incoloy-800 in the oxidizing and reducing conditions was also made. In nuclear industry, the presence of radiation field adds to the corrosion problems. The radiolysis products of water such as oxygen and hydrogen peroxide create an oxidizing environment that enhances the corrosion. Electrochemical studies at 90 °C showed that the reducing agents investigated were efficient in controlling corrosion processes in the presence of oxygen and hydrogen peroxide. Evaluation of thermal stability of hydrazine and its effect on corrosion potential of SS-304 LN were also investigated in the temperature range of 200–280 °C. The results showed that the thermal decomposition of hydrazine followed a first order kinetics. Besides, a change in electrochemical corrosion potential (ECP) was observed from −0.4 V (Vs SHE) to −0.67 V (Vs SHE) on addition of 5 ppm of hydrazine at 240 °C. Investigations were also made to understand the distribution behavior of hydrogen peroxide and hydrazine in water-steam phases and it was found that both the phases showed identical behavior. - Highlights: • Hydrazine was found to be a promising reducing agent for oxidant control. • In presence of hydrazine corrosion potential of SS304 LN was well below −230 mV. • SS304LN could be protected from IGSCC by hydrazine addition. • Thermal and radiation stability of hydrazine at 285 °C was found satisfactory.

  9. Nonlinear evolution of MHD instabilities

    International Nuclear Information System (INIS)

    Bateman, G.; Hicks, H.R.; Wooten, J.W.; Dory, R.A.

    1975-01-01

    A 3-D nonlinear MHD computer code was used to study the time evolution of internal instabilities. Velocity vortex cells are observed to persist into the nonlinear evolution. Pressure and density profiles convect around these cells for a weak localized instability, or convect into the wall for a strong instability. (U.S.)

  10. INDIVIDUALIZED YOGA FOR REDUCING DEPRESSION AND ANXIETY, AND IMPROVING WELL-BEING: A RANDOMIZED CONTROLLED TRIAL.

    Science.gov (United States)

    de Manincor, Michael; Bensoussan, Alan; Smith, Caroline A; Barr, Kylie; Schweickle, Monica; Donoghoe, Lee-Lee; Bourchier, Suzannah; Fahey, Paul

    2016-09-01

    Depression and anxiety are leading causes of disability worldwide. Current treatments are primarily pharmaceutical and psychological. Questions remain about effectiveness and suitability for different people. Previous research suggests potential benefits of yoga for reducing depression and anxiety. The aim of this study is to investigate the effects of an individualized yoga intervention. A sample of 101 people with symptoms of depression and/or anxiety participated in a randomized controlled trial comparing a 6-week yoga intervention with waitlist control. Yoga was additional to usual treatment. The control group was offered the yoga following the waitlist period. Measures included Depression Anxiety Stress Scale (DASS-21), Kessler Psychological Distress Scale (K10), Short-Form Health Survey (SF12), Scale of Positive and Negative Experience (SPANE), Flourishing Scale (FS), and Connor-Davidson Resilience Scale (CD-RISC2). There were statistically significant differences between yoga and control groups on reduction of depression scores (-4.30; 95% CI: -7.70, -0.01; P = .01; ES -.44). Differences in reduced anxiety scores were not statistically significant (-1.91; 95% CI: -4.58, 0.76; P = .16). Statistically significant differences in favor of yoga were also found on total DASS (P = .03), K10, SF12 mental health, SPANE, FS, and resilience scores (P stress and SF12 physical health scores were not statistically significant. Benefits were maintained at 6-week follow-up. Yoga plus regular care was effective in reducing symptoms of depression compared with regular care alone. Further investigation is warranted regarding potential benefits in anxiety. Individualized yoga may be particularly beneficial in mental health care in the broader community. © 2016 Wiley Periodicals, Inc.

  11. MapReduce Based Parallel Bayesian Network for Manufacturing Quality Control

    Science.gov (United States)

    Zheng, Mao-Kuan; Ming, Xin-Guo; Zhang, Xian-Yu; Li, Guo-Ming

    2017-09-01

    Increasing complexity of industrial products and manufacturing processes have challenged conventional statistics based quality management approaches in the circumstances of dynamic production. A Bayesian network and big data analytics integrated approach for manufacturing process quality analysis and control is proposed. Based on Hadoop distributed architecture and MapReduce parallel computing model, big volume and variety quality related data generated during the manufacturing process could be dealt with. Artificial intelligent algorithms, including Bayesian network learning, classification and reasoning, are embedded into the Reduce process. Relying on the ability of the Bayesian network in dealing with dynamic and uncertain problem and the parallel computing power of MapReduce, Bayesian network of impact factors on quality are built based on prior probability distribution and modified with posterior probability distribution. A case study on hull segment manufacturing precision management for ship and offshore platform building shows that computing speed accelerates almost directly proportionally to the increase of computing nodes. It is also proved that the proposed model is feasible for locating and reasoning of root causes, forecasting of manufacturing outcome, and intelligent decision for precision problem solving. The integration of bigdata analytics and BN method offers a whole new perspective in manufacturing quality control.

  12. Reducing TV watching during adult obesity treatment: two pilot randomized controlled trials.

    Science.gov (United States)

    Raynor, Hollie A; Steeves, Elizabeth Anderson; Bassett, David R; Thompson, Dixie L; Gorin, Amy A; Bond, Dale S

    2013-12-01

    The more time adults spend being sedentary, the greater the risk of obesity. The effect of reducing television (TV) watching, a prominent sedentary behavior, on weight loss has not been tested in an adult standard behavioral obesity intervention, and the mechanisms by which reducing TV watching influences energy balance behaviors are not well understood. Two, 8-week, pilot, randomized controlled trials were conducted examining the effect of a reduced TV watching prescription on energy balance behaviors and weight loss within an adult standard behavioral obesity intervention. In the first study, participants (n=24) were randomized into one of two conditions: (a) reduce energy intake and increase moderate to vigorous physical activity (MVPA) (INCREASE PA); or (b) reduce energy intake and decrease TV watching (DECREASE TV). As findings from the first pilot study did not show an increase in MVPA in the DECREASE TV group, the second study was designed to examine the effect of adding a reduced TV prescription to a standard intervention to optimize outcomes. In Pilot Study 2, participants (n=28) were randomized to INCREASE PA or to INCREASE PA+DECREASE TV. Outcomes included objectively measured TV watching and MVPA, self-reported light physical activity (LPA-Pilot Study 2 only), self-reported dietary intake while watching TV, and weight. Conditions with TV watching prescriptions significantly reduced TV watching. Both studies showed medium to large effect sizes for conditions with TV watching prescriptions to show greater reductions in dietary intake while watching TV. Pilot Study 1 found a trend for an increase in MVPA in INCREASE PA and Pilot Study 2 found significant increases in MVPA in both conditions. Pilot Study 2 found a significant increase in LPA in the INCREASE PA+DECREASE TV. Results indicate adding a TV watching prescription to a standard obesity intervention did not enhance increases in MVPA, but may assist with reducing dietary intake while TV watching and

  13. White-light parametric instabilities in plasmas.

    Science.gov (United States)

    Santos, J E; Silva, L O; Bingham, R

    2007-06-08

    Parametric instabilities driven by partially coherent radiation in plasmas are described by a generalized statistical Wigner-Moyal set of equations, formally equivalent to the full wave equation, coupled to the plasma fluid equations. A generalized dispersion relation for stimulated Raman scattering driven by a partially coherent pump field is derived, revealing a growth rate dependence, with the coherence width sigma of the radiation field, scaling with 1/sigma for backscattering (three-wave process), and with 1/sigma1/2 for direct forward scattering (four-wave process). Our results demonstrate the possibility to control the growth rates of these instabilities by properly using broadband pump radiation fields.

  14. Pulsating instabilities and chaos in lasers

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, R G; Biswas, D J

    1985-01-01

    A detailed state of the art survey of deterministic chaos in laser systems is presented. The mechanism of single mode instability is discussed, including spontaneous and induced mode splitting and the threshold for laser instabilities. Single mode homogeneously broadened systems are addressed, including optically pumped far infrared lasers and near-resonantly pumped midinfrared systems. Single mode inhomogeneously broadened systems are considered, including the He-Xe laser and the He-Ne laser at 3.39 microns. Single mode lasers with external control parameter are discussed, as is the multimode laser. 297 references.

  15. Triclade: influence of a sinuous secondary instability on the Richtmyer-Meshkov instabilities

    International Nuclear Information System (INIS)

    Boulet, M.; Griffond, J.

    2004-01-01

    Occurrence of a secondary instability developing after the Richtmyer-Meshkov (primary) instability is emphasized thanks to numerical simulations with the TRICLADE code. We are mainly considering 2D perturbations describes by trigonometric function cosine or [cosine]. However, the 3D case is also tackled. The sinuous secondary instability is characterized by the loss of the symmetries in the direction normal to the interface at its crests. It reduces the late time growing rate of the 'mushrooms' formed by the Richtmyer-Meshkov instability. Related simplified problems, like symmetrical Riemann problems or the Mallier-Maslowe array of counter-rotating vortices, allow us to perform 2D linear stability analysis. Thus, we show that the sinuous secondary instability is not a numerical artifact and that is comes from the continuous incompressible velocity field in the interface region. This instability implies temporal limitations for the validity of single mode simulations; therefore multimode simulations are necessary to study the ]ate-time behaviour of interfaces bitted by shocks. (authors)

  16. Oral cryotherapy reduces mucositis and opioid use after myeloablative therapy--a randomized controlled trial.

    Science.gov (United States)

    Svanberg, Anncarin; Birgegård, Gunnar; Ohrn, Kerstin

    2007-10-01

    Mucositis is a major complication in myeloablative therapy, which often necessitates advanced pharmacological pain treatment, including i.v. opioids. Attempts to prevent oral mucositis have included oral cryotherapy, which has been shown to reduce mucositis, but there is a lack of knowledge concerning the effect of oral cryotherapy on opioid use by reducing the mucositis for patients treated with myeloablative therapy before bone marrow transplantation (BMT). The aim of the present study was to evaluate if oral cryotherapy could delay or alleviate the development of mucositis and thereby reduce the number of days with i.v. opioids among patients who receive myeloablative therapy before BMT. Eighty patients 18 years and older, scheduled for BMT, were included consecutively and randomised to oral cryotherapy or standard oral care. A stratified randomisation was used with regard to type of transplantation. Intensity of pain, severity of mucositis and use of opioids were recorded using pain visual analogue scale (VAS) scores, mucositis index scores and medical and nursing charts. This study showed that patients receiving oral cryotherapy had less pronounced mucositis and significantly fewer days with i.v. opioids than the control group. In the autologous setting, cryotherapy patients also needed significantly lower total dose of opioids. Oral cryotherapy is an effective and well-tolerated therapy to alleviate mucositis and consequently reduce the number of days with i.v. opioids among patients treated with myeloablative therapy before BMT.

  17. Exercise training reduces the frequency of menopausal hot flushes by improving thermoregulatory control.

    Science.gov (United States)

    Bailey, Tom G; Cable, N Timothy; Aziz, Nabil; Dobson, Rebecca; Sprung, Victoria S; Low, David A; Jones, Helen

    2016-07-01

    Postmenopausal hot flushes occur due to a reduction in estrogen production causing thermoregulatory and vascular dysfunction. Exercise training enhances thermoregulatory control of sweating, skin and brain blood flow. We aimed to determine if improving thermoregulatory control and vascular function with exercise training alleviated hot flushes. Twenty-one symptomatic women completed a 7-day hot flush questionnaire and underwent brachial artery flow-mediated dilation and a cardiorespiratory fitness test. Sweat rate and skin blood flow temperature thresholds and sensitivities, and middle cerebral artery velocity (MCAv) were measured during passive heating. Women performed 16 weeks of supervised exercise training or control, and measurements were repeated. There was a greater improvement in cardiorespiratory fitness (4.45 mL/kg/min [95% CI: 1.87, 8.16]; P = 0.04) and reduced hot flush frequency (48 hot flushes/wk [39, 56]; P core temperature (0.14°C [0.01, 0.27]; P = 0.03) and increased basal MCAv (2.8 cm/s [1.0, 5.2]; P = 0.04) compared with control. Sweat rate and skin blood flow thresholds occurred approximately 0.19°C and 0.17°C earlier, alongside improved sweating sensitivity with exercise. MCAv decreased during heating (P training that improves cardiorespiratory fitness reduces self-reported hot flushes. Improvements are likely mediated through greater thermoregulatory control in response to increases in core temperature and enhanced vascular function in the cutaneous and cerebral circulations.

  18. Early control of distal internal carotid artery during carotid endarterectomy: does it reduce cerebral microemboli?

    Science.gov (United States)

    Mommertz, G; Das, M; Langer, S; Koeppel, T A; Krings, T; Mess, W H; Schiefer, J; Jacobs, M J

    2010-06-01

    According to the results of the large trials on carotid endarterectomy (CEA), this type of surgery is only warranted if perioperative mortality and morbidity are kept considerably low. Less attention has been paid to methods of cerebral protection during CEA, although intraoperative transcranial Doppler (TCD) can visualise intracerebral microemboli (MES) during routine carotid dissection, although MES occur throughout the CEA, only those during dissection are related to neurological outcome. Prevention of MES by means of early control of the distal internal carotid artery dislodging from the carotid artery plaque during dissection is very likely the mechanism behind an eventual benefit from this approach. Hence, the amount of MES might serve as a surrogate parameter for the risk of periprocedural neurological events. So, the aim of the present study was to evaluate whether early control of the distal carotid artery during CEA is capable of reducing the number of MES by means of a prospective randomised trial. Twenty-eight patients (29 procedures) could be prospectively included in our study. Before surgery we randomly assigned the patients to two groups: group A (N.=12): CEA by means of early control of the distal internal carotid artery; group B (N.=17): CEA with dissection of the total carotid bifurcation before clamping the arteries. Periprocedurally, we continuously monitored the cerebral blood flow in the ipsilateral middle cerebral artery by means of TCD. Pre- and postoperative morbidity were independently verified by a neurologist control of the distal internal carotid artery did not reduce the occurrence of MES during dissection of the carotid bifurcation. Also, the total number of MES throughout the procedure and postoperatively was comparable between both groups. The procedure related times as well as the clinical outcome did not differ significantly. Thus, early control of the distal internal carotid artery has got no advantage but also no disadvantage

  19. Electronic laboratory system reduces errors in National Tuberculosis Program: a cluster randomized controlled trial.

    Science.gov (United States)

    Blaya, J A; Shin, S S; Yale, G; Suarez, C; Asencios, L; Contreras, C; Rodriguez, P; Kim, J; Cegielski, P; Fraser, H S F

    2010-08-01

    To evaluate the impact of the e-Chasqui laboratory information system in reducing reporting errors compared to the current paper system. Cluster randomized controlled trial in 76 health centers (HCs) between 2004 and 2008. Baseline data were collected every 4 months for 12 months. HCs were then randomly assigned to intervention (e-Chasqui) or control (paper). Further data were collected for the same months the following year. Comparisons were made between intervention and control HCs, and before and after the intervention. Intervention HCs had respectively 82% and 87% fewer errors in reporting results for drug susceptibility tests (2.1% vs. 11.9%, P = 0.001, OR 0.17, 95%CI 0.09-0.31) and cultures (2.0% vs. 15.1%, P Chasqui users sent on average three electronic error reports per week to the laboratories. e-Chasqui reduced the number of missing laboratory results at point-of-care health centers. Clinical users confirmed viewing electronic results not available on paper. Reporting errors to the laboratory using e-Chasqui promoted continuous quality improvement. The e-Chasqui laboratory information system is an important part of laboratory infrastructure improvements to support multidrug-resistant tuberculosis care in Peru.

  20. Intensive postoperative glucose control reduces the surgical site infection rates in gynecologic oncology patients.

    Science.gov (United States)

    Al-Niaimi, Ahmed N; Ahmed, Mostafa; Burish, Nikki; Chackmakchy, Saygin A; Seo, Songwon; Rose, Stephen; Hartenbach, Ellen; Kushner, David M; Safdar, Nasia; Rice, Laurel; Connor, Joseph

    2015-01-01

    SSI rates after gynecologic oncology surgery vary from 5% to 35%, but are up to 45% in patients with diabetes mellitus (DM). Strict postoperative glucose control by insulin infusion has been shown to lower morbidity, but not specifically SSI rates. Our project studied continuous postoperative insulin infusion for 24h for gynecologic oncology patients with DM and hyperglycemia with a target blood glucose of controlled with intermittent subcutaneous insulin injections. Group 2 was composed of patients with DM and postoperative hyperglycemia whose blood glucose was controlled by insulin infusion. Group 3 was composed of patients with neither DM nor hyperglycemia. We controlled for all relevant factors associated with SSI. We studied a total of 372 patients. Patients in Group 2 had an SSI rate of 26/135 (19%), similar to patients in Group 3 whose rate was 19/89 (21%). Both were significantly lower than the SSI rate (43/148, 29%) of patients in Group 1. This reduction of 35% is significant (p = 0.02). Multivariate analysis showed an odd ratio = 0.5 (0.28-0.91) in reducing SSI rates after instituting this protocol. Initiating intensive glycemic control for 24h after gynecologic oncology surgery in patients with DM and postoperative hyperglycemia lowers the SSI rate by 35% (OR = 0.5) compared to patients receiving intermittent sliding scale insulin and to a rate equivalent to non-diabetics. Copyright © 2014. Published by Elsevier Inc.

  1. Coordinated Control of Wind Turbine and Energy Storage System for Reducing Wind Power Fluctuation

    Energy Technology Data Exchange (ETDEWEB)

    Muljadi, Eduard [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Kim, Chunghun [Hanyang University; Chung, Chung Choo [Hanyang University

    2017-11-13

    This paper proposes a coordinated control of wind turbine and energy storage system (ESS). Because wind power (WP) is highly dependent on variable wind speed and could induce a severe stability problem to power system especially when the WP has high penetration level. To solve this problem, many power generation corporations or grid operators recently use the ESS. It has very quick response and good performance for reducing the impact of WP fluctuation but has high cost for its installation. Therefore, it is very important to design the control algorithm considering both ESS capacity and grid reliability. Thus, we propose the control algorithm to mitigate the WP fluctuation by using the coordinated control between wind turbine and ESS considering ESS state of charge (SoC) and the WP fluctuation. From deloaded control according to WP fluctuation and ESS SoC management, we can expect the ESS lifespan expansion and improved grid reliability. The effectiveness of the proposed method is validated in MATLAB/Simulink considering power system including both wind turbine generator and conventional generators which react to system frequency deviation.

  2. A videotaped intervention to enhance child control and reduce anxiety of the pain of dental injections.

    Science.gov (United States)

    Weinstein, P; Raadal, M; Naidu, S; Yoshida, T; Kvale, G; Milgrom, P

    2003-12-01

    While the psychological literature shows that perceptions of uncontrollability contribute to anxiety and other pathologies, interventions that enhance perceived control have been shown to reduce anxiety. This study attempted to assess a brief videotape to enhance child perceived control in a dental setting. 101 children aged 7-9 years completed warm-up procedures and viewed either: a) the experimental intervention, a 2 minutes video of a dentist explaining what an injection will feel like and proposing hand raising as a signal mechanism; or b) the control condition, a 2 minutes video of Disneyland. Fear of dental injections was assessed on a 10 cm visual analogue scale before and after the intervention. In the experimental group there was a significant fear reduction from pre- to post-intervention, while this was not the case in the control group. Children with higher pre-existing levels of fear benefited more from the intervention than children with lower levels of fear. The results of this pilot study suggest that intervention packages that impact child control have promise in lowering anxiety.

  3. Instabilities in strongly coupled plasmas

    CERN Document Server

    Kalman, G J

    2003-01-01

    The conventional Vlasov treatment of beam-plasma instabilities is inappropriate when the plasma is strongly coupled. In the strongly coupled liquid state, the strong correlations between the dust grains fundamentally affect the conditions for instability. In the crystalline state, the inherent anisotropy couples the longitudinal and transverse polarizations, and results in unstable excitations in both polarizations. We summarize analyses of resonant and non-resonant, as well as resistive instabilities. We consider both ion-dust streaming and dust beam-plasma instabilities. Strong coupling, in general, leads to an enhancement of the growth rates. In the crystalline phase, a resonant transverse instability can be excited.

  4. Orphans and political instability.

    Science.gov (United States)

    Breuning, Marijke; Ishiyama, John

    2011-01-01

    This study investigates the security implications of growing orphan populations, particularly in Sub-Saharan Africa. Little has been written about the security implications of this especially vulnerable group of children. Are growing orphan populations associated with increases in political instability as has been suggested? Using data from several sources, we employ regression analysis to test whether Sub-Saharan African countries with larger proportions of orphans and those with increasing orphan populations experience higher rates of political instability. We find that the increase in the orphan population is related to an increasing incidence of civil conflict, but do not find a similar relationship for the proportion of orphans. In addition, we find that the causes of orphanhood matter. We conclude that increases in orphan populations (rather than simple proportions) are destabilizing. We suggest possible avenues for mediating the security risks posed by growing orphan populations.

  5. A trickle instability

    Science.gov (United States)

    Bossa, Benjamin

    2005-11-01

    We address the problem of the free fall of a long, horizontal and narrow liquid layer squeezed in a vertical open Hele-Shaw cell. The layer destabilizes as it falls down, evolving into a series of liquid blobs linked together by thin bridges, which ultimately break, leaving the initially connex fluid layer as a set a disjointed drops. The mechanism of this instability is the onset of a vertical pressure gradient due to the curvature difference of the moving contact line between the advancing interface and the rear interface. This instability, whose growth rate scales with a non-trivial power of the capillary number, amplifies indifferently a broad band of wavenumbers because of the flat shape of its dispersion relation in the thin layer limit. We will finally comment on the nature of the final fragmentation process and drop size distributions.

  6. Instability and internet design

    Directory of Open Access Journals (Sweden)

    Sandra Braman

    2016-09-01

    Full Text Available Instability - unpredictable but constant change in one’s environment and the means with which one deals with it - has replaced convergence as the focal problem for telecommunications policy in general and internet policy in particular. Those who designed what we now call the internet during the first decade of the effort (1969-1979, who in essence served simultaneously as its policy-makers, developed techniques for coping with instability of value for network designers today and for those involved with any kind of large-scale sociotechnical infrastructure. Analysis of the technical document series that was medium for and record of that design process reveals coping techniques that began with defining the problem and went on to include conceptual labour, social practices, and technical approaches.

  7. Imaging of patellofemoral instability

    International Nuclear Information System (INIS)

    Waldt, S.; Rummeny, E.J.

    2012-01-01

    Patellofemoral instability remains a diagnostic and therapeutic challenge due to its multifactorial genesis. The purpose of imaging is to systematically analyze predisposing factors, such as trochlear dysplasia, patella alta, tibial tuberosity-trochlear groove (TT-TG) distance, rotational deformities of the lower limb and patellar tilt. In order to evaluate anatomical abnormalities with a sufficient diagnostic accuracy, standardized measurement methods and implementation of various imaging modalities are necessary. Diagnosis of acute and often overlooked lateral patellar dislocation can be established with magnetic resonance imaging (MRI) because of its characteristic patterns of injury. Damage to the medial patellofemoral ligament (MPFL) has a significance just as high as the predisposing risk factors in relation to the cause of chronic instability. (orig.) [de

  8. Linear waves and instabilities

    International Nuclear Information System (INIS)

    Bers, A.

    1975-01-01

    The electrodynamic equations for small-amplitude waves and their dispersion relation in a homogeneous plasma are outlined. For such waves, energy and momentum, and their flow and transformation, are described. Perturbation theory of waves is treated and applied to linear coupling of waves, and the resulting instabilities from such interactions between active and passive waves. Linear stability analysis in time and space is described where the time-asymptotic, time-space Green's function for an arbitrary dispersion relation is developed. The perturbation theory of waves is applied to nonlinear coupling, with particular emphasis on pump-driven interactions of waves. Details of the time--space evolution of instabilities due to coupling are given. (U.S.)

  9. Cosmic ray driven instability

    International Nuclear Information System (INIS)

    Dorfi, E.A.; Drury, L.O.

    1985-01-01

    The interaction between energetic charged particles and thermal plasma, which forms the basis of diffusive shock acceleration, leads also to interesting dynamical phenomena. For a compressional mode propagating in a system with homoeneous energetic particle pressure it is well known that friction with the energetic particles leads to damping. The linear theory of this effect has been analyzed in detail by Ptuskin. Not so obvious is that a non-uniform energetic particle pressure can in addition amplify compressional disturbances. If the pressure gradient is sufficiently steep this growth can dominate the frictional damping and lead to an instability. It is important to not that this effect results from the collective nature of the interaction between the energetic particles and the gas and is not connected with the Parker instability, nor with the resonant amplification of Alfven waves

  10. Modification of Flow Structure Over a Van Model By Suction Flow Control to Reduce Aerodynamics Drag

    Directory of Open Access Journals (Sweden)

    Harinaldi Harinaldi

    2012-05-01

    Full Text Available Automobile aerodynamic studies are typically undertaken to improve safety and increase fuel efficiency as well as to  find new innovation in automobile technology to deal with the problem of energy crisis and global warming. Some car companies have the objective to develop control solutions that enable to reduce the aerodynamic drag of vehicle and  significant modification progress is still possible by reducing the mass, rolling friction or aerodynamic drag. Some flow  control method provides the possibility to modify the flow separation to reduce the development of the swirling structures around the vehicle. In this study, a family van is modeled with a modified form of Ahmed's body by changing the orientation of the flow from its original form (modified/reversed Ahmed body. This model is equipped with a suction on the rear side to comprehensively examine the pressure field modifications that occur. The investigation combines computational and experimental work. Computational approach used  a commercial software with standard k-epsilon flow turbulence model, and the objectives was  to determine the characteristics of the flow field and aerodynamic drag reduction that occurred in the test model. Experimental approach used load cell in order to validate the aerodynamic drag reduction obtained by computational approach. The results show that the application of a suction in the rear part of the van model give the effect of reducing the wake and the vortex formation. Futhermore, aerodynamic drag reduction close to 13.86% for the computational approach and 16.32% for the experimental have been obtained.

  11. Effects of reducing children's television and video game use on aggressive behavior: a randomized controlled trial.

    Science.gov (United States)

    Robinson, T N; Wilde, M L; Navracruz, L C; Haydel, K F; Varady, A

    2001-01-01

    The relationship between exposure to aggression in the media and children's aggressive behavior is well documented. However, few potential solutions have been evaluated. To assess the effects of reducing television, videotape, and video game use on aggressive behavior and perceptions of a mean and scary world. Randomized, controlled, school-based trial. Two sociodemographically and scholastically matched public elementary schools in San Jose, Calif. Third- and fourth-grade students (mean age, 8.9 years) and their parents or guardians. Children in one elementary school received an 18-lesson, 6-month classroom curriculum to reduce television, videotape, and video game use. In September (preintervention) and April (postintervention) of a single school year, children rated their peers' aggressive behavior and reported their perceptions of the world as a mean and scary place. A 60% random sample of children were observed for physical and verbal aggression on the playground. Parents were interviewed by telephone and reported aggressive and delinquent behaviors on the child behavior checklist. The primary outcome measure was peer ratings of aggressive behavior. Compared with controls, children in the intervention group had statistically significant decreases in peer ratings of aggression (adjusted mean difference, -2.4%; 95% confidence interval [CI], -4.6 to -0.2; P =.03) and observed verbal aggression (adjusted mean difference, -0.10 act per minute per child; 95% CI, -0.18 to -0.03; P =.01). Differences in observed physical aggression, parent reports of aggressive behavior, and perceptions of a mean and scary world were not statistically significant but favored the intervention group. An intervention to reduce television, videotape, and video game use decreases aggressive behavior in elementary schoolchildren. These findings support the causal influences of these media on aggression and the potential benefits of reducing children's media use.

  12. Preliminary study of Rayleigh-Taylor instability in wire-array Z-pinch

    International Nuclear Information System (INIS)

    He Kaihui; Feng Kaiming; Li Qiang; Gao Chunming

    2000-01-01

    It is important to research into the MHD Rayleigh-Taylor instability developed in Z-pinch implosion. A snowplough model of the single wire Z-pinch is presented. The perturbation amplitude of Rayleigh-Taylor instability in the wire-array Z-pinch is analyzed quantitatively. Sheared axial flow is put forward to mitigate and reduce the Rayleigh-Taylor instability. And other approaches used to mitigate MHD instability in such a super-fast process are explored

  13. Instability in dynamic fracture

    Science.gov (United States)

    Fineberg, J.; Marder, M.

    1999-05-01

    The fracture of brittle amorphous materials is an especially challenging problem, because the way a large object shatters is intimately tied to details of cohesion at microscopic scales. This subject has been plagued by conceptual puzzles, and to make matters worse, experiments seemed to contradict the most firmly established theories. In this review, we will show that the theory and experiments fit within a coherent picture where dynamic instabilities of a crack tip play a crucial role. To accomplish this task, we first summarize the central results of linear elastic dynamic fracture mechanics, an elegant and powerful description of crack motion from the continuum perspective. We point out that this theory is unable to make predictions without additional input, information that must come either from experiment, or from other types of theories. We then proceed to discuss some of the most important experimental observations, and the methods that were used to obtain the them. Once the flux of energy to a crack tip passes a critical value, the crack becomes unstable, and it propagates in increasingly complicated ways. As a result, the crack cannot travel as quickly as theory had supposed, fracture surfaces become rough, it begins to branch and radiate sound, and the energy cost for crack motion increases considerably. All these phenomena are perfectly consistent with the continuum theory, but are not described by it. Therefore, we close the review with an account of theoretical and numerical work that attempts to explain the instabilities. Currently, the experimental understanding of crack tip instabilities in brittle amorphous materials is fairly detailed. We also have a detailed theoretical understanding of crack tip instabilities in crystals, reproducing qualitatively many features of the experiments, while numerical work is beginning to make the missing connections between experiment and theory.

  14. Instabilities in the plasma focus

    International Nuclear Information System (INIS)

    Kaeppeler, H.J.

    1975-03-01

    The plasma focus was studied by many research teams in view of a possible approach to controlled thermonuclear fusion. Though it is questionable whether the plasma focus will ever lead to a fusion reactor, it nevertheless constitutes a strong source of neutron, X- and gamma radiation for simulating fusion reactor conditions. Furthermore, the plasma focus yields very high temperatures (10 7 K) and densities (> 10 19 cm -3 ) and thus provides interesting conditions for the study of high density plasmas. This review paper starts with a description of the compression stage of the focussing plasma, using a snow-plough model. It is shown that sophisticated MHD calculations substantiate the snowplough theory, but are not suited to describe the phenomena in the final compressed stage. For this purpose, a particle-in-cell calculation is employed, yielding a beam-beam collision model for the neutron production. Experimental evidence indicates that neutron production is associated with the appearence of m = O instabilities and is the direct result of collisions between anomalously accelerated ions. One of the mechanisms of ion acceleration are strong local electric fields. Another possible mechanism can bee seen in beam-plasma instabilities caused by runaway electrons. The analytical derivation of the dispersion relation for plasma focus conditions including runaway effect is discussed (orig.) [de

  15. Reduced-impact sliding pressure control valve for pneumatic hammer drill

    Science.gov (United States)

    Polsky, Yarom [Oak Ridge, TN; Grubelich, Mark C [Albuquerque, NM; Vaughn, Mark R [Albuquerque, NM

    2012-05-15

    A method and means of minimizing the effect of elastic valve recoil in impact applications, such as percussive drilling, where sliding spool valves used inside the percussive device are subject to poor positioning control due to elastic recoil effects experienced when the valve impacts a stroke limiting surface. The improved valve design reduces the reflected velocity of the valve by using either an energy damping material, or a valve assembly with internal damping built-in, to dissipate the compression stress wave produced during impact.

  16. Lane Changing Control to Reduce Traffic Load Effect on Long-Span Bridges

    OpenAIRE

    Caprani, Colin C; Enright, Bernard; Carey, Colm

    2012-01-01

    Long span bridges are critical parts of a nation’s infrastructure network and congested traffic loading is the governing form of traffic loading. Groups of trucks travelling in conveys are created when fast-er moving vehicles, such as cars, change lane. In this research the authors investigate how the control of these lane-changing events can help reduce the traffic load effects on long span bridges. Real traffic data is used to simulate a traffic stream on a virtual road and bridge using a m...

  17. Reduced waste arise in a reprocessing plant by the use of remote control

    International Nuclear Information System (INIS)

    Issel, W.A.

    1988-01-01

    This paper discusses how the increasing use of remote controlled processes, which is unavoidable with respect to work in hostile environment and which after serious further development and experience may improve plant production rate lead to another benefit in handling nuclear material, the benefit of reducing waste production and by this the avoidance of radioactive dispersal. The example of reprocessing of spent fuel is shown, what consequences and what improvements can be expected in the waste management by remote handling and maintenance instead of direct intervention by men

  18. Relativistic centrifugal instability

    Science.gov (United States)

    Gourgouliatos, Konstantinos N.; Komissarov, Serguei S.

    2018-03-01

    Near the central engine, many astrophysical jets are expected to rotate about their axis. Further out they are expected to go through the processes of reconfinement and recollimation. In both these cases, the flow streams along a concave surface and hence, it is subject to the centrifugal force. It is well known that such flows may experience the centrifugal instability (CFI), to which there are many laboratory examples. The recent computer simulations of relativistic jets from active galactic nuclei undergoing the process of reconfinement show that in such jets CFI may dominate over the Kelvin-Helmholtz instability associated with velocity shear (Gourgouliatos & Komissarov). In this letter, we generalize the Rayleigh criterion for CFI in rotating fluids to relativistic flows using a heuristic analysis. We also present the results of computer simulations which support our analytic criterion for the case of an interface separating two uniformly rotating cylindrical flows. We discuss the difference between CFI and the Rayleigh-Taylor instability in flows with curved streamlines.

  19. Ion temperature gradient instability

    International Nuclear Information System (INIS)

    1989-01-01

    Anomalous ion thermal conductivity remains an open physics issue for the present generation of high temperature Tokamaks. It is generally believed to be due to Ion Temperature Gradient Instability (η i mode). However, it has been difficult, if not impossible to identify this instability and study the anomalous transport due to it, directly. Therefore the production and identification of the mode is pursued in the simpler and experimentally convenient configuration of the Columbia Linear Machine (CLM). CLM is a steady state machine which already has all the appropriate parameters, except η i . This parameter is being increased to the appropriate value of the order of 1 by 'feathering' a tungsten screen located between the plasma source and the experimental cell to flatten the density profile and appropriate redesign of heating antennas to steepen the ion temperature profile. Once the instability is produced and identified, a thorough study of the characteristics of the mode can be done via a wide range of variation of all the critical parameters: η i , parallel wavelength, etc

  20. The efficacy of a movement control exercise programme to reduce injuries in youth rugby: a cluster randomised controlled trial

    Science.gov (United States)

    Hislop, M D; Stokes, K A; Williams, S; McKay, C D; England, M; Kemp, S P T

    2016-01-01

    Background Injuries to youth rugby players have become an increasingly prominent health concern, highlighting the importance of developing and implementing appropriate preventive strategies. A growing body of evidence from other youth sports has demonstrated the efficacy of targeted exercise regimens to reduce injury risk. However, studies have yet to investigate the effect of such interventions in youth contact sport populations like rugby union. Objective To determine the efficacy of an evidence-based movement control exercise programme compared with a sham exercise programme to reduce injury risk in youth rugby players. Exercise programme compliance between trial arms and the effect of coach attitudes on compliance will also be evaluated. Setting School rugby coaches in England will be the target of the researcher intervention, with the effects of the injury prevention programmes being measured in male youth players aged 14–18 years in school rugby programmes over the 2015–2016 school winter term. Methods A cluster-randomised controlled trial with schools randomly allocated to either a movement control exercise programme or a sham exercise programme, both of which are coach-delivered. Injury measures will derive from field-based injury surveillance, with match and training exposure and compliance recorded. A questionnaire will be used to evaluate coach attitudes, knowledge, beliefs and behaviours both prior to and on the conclusion of the study period. Outcome measures Summary injury measures (incidence, severity and burden) will be compared between trial arms, as will the influence of coach attitudes on compliance and injury burden. Additionally, changes in these outcomes through using the exercise programmes will be evaluated. Trial registration number ISRTCNN13422001. PMID:27900148

  1. Efficacy of aromatherapy for reducing pain during labor: a randomized controlled trial.

    Science.gov (United States)

    Tanvisut, Rajavadi; Traisrisilp, Kuntharee; Tongsong, Theera

    2018-05-01

    Many strategies for labor pain management have been studied, including aromatherapy, which is a noninvasive, alternative medicine used as an adjunct for labor pain control. Nevertheless, the results were contradictory. Therefore, we conducted this study to determine the effectiveness of aromatherapy for reducing pain during labor. A randomized controlled trial was carried out on Thai laboring primigravidae who were a low-risk singleton pregnancy undergoing vaginal delivery. All participants, both study and control group, received standard obstetric care. Aromatherapy was only provided to the study group during the first stage of labor. The women rated their pain intensity by rating scales at different stages of labor. The primary outcome was pain scores and the secondary outcomes were necessity of painkiller usage, labor time, aromatherapy-associated complications, route of delivery, and Apgar scores. A total of 104 women were recruited, 52 in each group. Baseline characteristics and baseline pain scores were comparable. The median pain score of latent and early active phase was lower in the aromatherapy group, 5 vs 6 and 7 vs 8, respectively. The mean differences of pain scores between latent and early active phase and the baseline were significantly lower in the aromatherapy group, 1.88 vs 2.6 (p = 0.010) and 3.82 vs 4.39 (p = 0.031), respectively. Late active phase pain scores and other perinatal outcomes were not significantly different. Aromatherapy is helpful in reducing pain in latent and early active phase, and can probably be used as an adjunctive method for labor pain control without serious side effects.

  2. An empirical study of the effectiveness of electronic stability control system in reducing loss of vehicle control.

    Science.gov (United States)

    Papelis, Yiannis E; Watson, Ginger S; Brown, Timothy L

    2010-05-01

    A significant percentage of fatal vehicle crashes involve loss of control (LOC). Electronic stability control (ESC) is an active safety system that detects impending LOC and activates counter-measures that help the driver maintain or re-gain control. To assess the effectiveness of ESC in preventing LOC, an empirical study was conducted on a high-fidelity driving simulator. The ESC systems for two vehicles were incorporated into the simulator's dynamics code which was calibrated to ensure engineering validation. The study utilized three scenarios designed to recreate typical LOC situations, and was designed to assess the effects of ESC presence, vehicle type, scenario, age and gender. A total of 120 research participants completed the study. Results showed a statistically significant reduction in LOC with ESC compared to without ESC (F=52.72, p<0.0001). The study findings of 5% LOC with ESC and 30% without ESC match several epidemiological studies that have analyzed ESC effectiveness on real-world crashes, providing strong support to the use of driving simulation for studying driver behavior. Study conclusions suggest that wide-spread utilization of ESC is likely to reduce traffic fatalities. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  3. Design of Controller for Reducing In-Rush Current of Single-Phase Induction Motor

    Energy Technology Data Exchange (ETDEWEB)

    Park, Su Kang; Baek, Hyung Lae; Lee, Sang Il [Chosun University, Kwangju (Korea)

    2001-05-01

    During an AC motor's start-up accelerating period, a large amount of current is required to reach to the rating speed. This is called in-rush current. This peak in-rush current can be more than about several times the operating or steady-state current in the full load rating of the motor. In-rush current is present in both and electronic ballasts. The main area of concern is the tripping of circuit breaker and fuses which can affect electrical system components From this, we can see that the electrical power controllers will be rather concerned, since they have to supply the actual current necessary to start the motor. This paper presents a new method to reducing in-rush current and energy saving of the single-phase induction motor used in air-conditioner. It can be obtained that proposed system is low cost and small size as compared with other controller. Experiments are focused on a capacitor starting single-phase induction motor. The optimal power saving and in-rush current limiting by phase angle control are verified by experimental results. Also, auxiliary winding was controlled by electronic starting switch. (author). 10 refs., 13 figs., 2 tabs.

  4. Reducing Runoff Loss of Applied Nutrients in Oil Palm Cultivation Using Controlled-Release Fertilizers

    Directory of Open Access Journals (Sweden)

    A. Bah

    2014-01-01

    Full Text Available Controlled-release fertilizers are expected to minimize nutrient loss from crop fields due to their potential to supply plant-available nutrients in synchrony with crop requirements. The evaluation of the efficiency of these fertilizers in tropical oil palm agroecological conditions is not yet fully explored. In this study, a one-year field trial was conducted to determine the impact of fertilization with water soluble conventional mixture and controlled-release fertilizers on runoff loss of nutrients from an immature oil palm field. Soil and nutrient loss were monitored for one year in 2012/2013 under erosion plots of 16 m2 on 10% slope gradient. Mean sediments concentration in runoff amounted to about 6.41 t ha−1. Conventional mixture fertilizer posed the greatest risk of nutrient loss in runoff following fertilization due to elevated nitrogen (6.97%, potassium (13.37%, and magnesium (14.76% as percentage of applied nutrients. In contrast, this risk decreased with the application of controlled-release fertilizers, representing 0.75–2.44% N, 3.55–5.09% K, and 4.35–5.43% Mg loss. Meanwhile, nutrient loss via eroded sediments was minimal compared with loss through runoff. This research demonstrates that the addition of controlled-release fertilizers reduced the runoff risks of nutrient loss possibly due to their slow-release properties.

  5. Revisited study of fluorine implantation impact on negative bias temperature instability for input/output device of automotive micro controller unit

    Science.gov (United States)

    Yoshida, Tetsuya; Maekawa, Keiichi; Tsuda, Shibun; Shimizu, Tatsuo; Ogasawara, Makoto; Aono, Hideki; Yamaguchi, Yasuo

    2018-04-01

    We investigate the effect of fluorine implanted in the polycrystalline silicon (poly-Si) gate and source/drain (S/D) region on negative bias temperature instability (NBTI) improvement. It is found that there is a trade-off implantation energy dependence of NBTI between fluorine in the poly-Si gate and that in the S/D region. Fluorine implanted in the poly-Si gate contributes to NBTI improvement under low energy implantation. On the other hand, NBTI is improved by fluorine implanted in the S/D region under high energy. We propose that the two-step implantation process with high and low energy is the optimum condition for NBTI improvement.

  6. Does Enhancing Work-Time Control and Flexibility Reduce Turnover? A Naturally Occurring Experiment.

    Science.gov (United States)

    Moen, Phyllis; Kelly, Erin L; Hill, Rachelle

    2011-02-01

    We investigate the turnover effects of an organizational innovation (ROWE-Results Only Work Environment) aimed at moving away from standard time practices to focus on results rather than time spent at work. To model rates of turnover, we draw on survey data from a sample of employees at a corporate headquarters (N = 775) and institutional records of turnover over eight months following the ROWE implementation. We find the odds of turnover are indeed lower for employees participating in the ROWE initiative, which offers employees greater work-time control and flexibility, and that this is the case regardless of employees' gender, age, or family life stage. ROWE also moderates the turnover effects of organizational tenure and negative home-to-work spillover, physical symptoms, and job insecurity, with those in ROWE who report these situations generally less likely to leave the organization. Additionally, ROWE reduces turnover intentions among those remaining with the corporation. This research moves the "opting-out" argument from one of private troubles to an issue of greater employee work-time control and flexibility by showing that an organizational policy initiative can reduce turnover.

  7. Reward reduces conflict by enhancing attentional control and biasing visual cortical processing.

    Science.gov (United States)

    Padmala, Srikanth; Pessoa, Luiz

    2011-11-01

    How does motivation interact with cognitive control during challenging behavioral conditions? Here, we investigated the interactions between motivation and cognition during a response conflict task and tested a specific model of the effect of reward on cognitive processing. Behaviorally, participants exhibited reduced conflict during the reward versus no-reward condition. Brain imaging results revealed that a group of subcortical and fronto-parietal regions was robustly influenced by reward at cue processing and, importantly, that cue-related responses in fronto-parietal attentional regions were predictive of reduced conflict-related signals in the medial pFC (MPFC)/ACC during the upcoming target phase. Path analysis revealed that the relationship between cue responses in the right intraparietal sulcus (IPS) and interference-related responses in the MPFC during the subsequent target phase was mediated via signals in the left fusiform gyrus, which we linked to distractor-related processing. Finally, reward increased functional connectivity between the right IPS and both bilateral putamen and bilateral nucleus accumbens during the cue phase, a relationship that covaried with across-individual sensitivity to reward in the case of the right nucleus accumbens. Taken together, our findings are consistent with a model in which motivationally salient cues are employed to upregulate top-down control processes that bias the selection of visual information, thereby leading to more efficient stimulus processing during conflict conditions.

  8. Interventions to reduce postpartum stress in first-time mothers: a randomized-controlled trial.

    Science.gov (United States)

    Osman, Hibah; Saliba, Matilda; Chaaya, Monique; Naasan, Georges

    2014-10-15

    The postpartum period can be a challenging time particularly for first-time mothers. This study aimed to assess two different interventions designed to reduce stress in the postpartum among first-time mothers. Healthy first-time mothers with healthy newborns were recruited from hospitals in Beirut, Lebanon after delivery. The two interventions were a 20-minute film addressing common stressors in the postpartum period and a 24-hour telephone support hotline. Participants were randomized to one of four study arms to receive either the postpartum support film, the hotline service, both interventions, or a music CD (control). Participants were interviewed at eight to twelve weeks postpartum for assessment of levels of stress as measured by the Cohen Perceived Stress Scale (PSS-10). Of the 632 eligible women, 552 (88%) agreed to participate in the study. Of those, 452 (82%) completed the study. Mean PSS-10 scores of mothers who received the film alone (15.76) or the film with the hotline service (15.86) were significantly lower than that of the control group (18.93) (p-value film and the 24-hour telephone hotline service reduced stress in the postpartum period in first-time mothers. These simple interventions can be easily implemented and could have an important impact on the mental wellbeing of new mothers. The trial was registered with clinicaltrials.gov (identifier # NCT00857051) on March 5, 2009.

  9. An intervention to preschool children for reducing screen time: a randomized controlled trial.

    Science.gov (United States)

    Yilmaz, G; Demirli Caylan, N; Karacan, C D

    2015-05-01

    Screen time, defined as time spent watching television, DVDs, or videos or playing computer or video games, has been related to serious health consequences in children, such as impaired language acquisition, violent behaviour, tobacco smoking and obesity. Our aim was to determine if a simple intervention aimed at preschool-aged children, applied at the health maintenance visits, in the primary care setting, would be effective in reducing screen time. We used a two group randomized controlled trial design. Two- to 6-year-old children and their parents were randomly assigned to receive an intervention to reduce their screen time, BMI and parental report of aggressive behaviour. At the end of the intervention we made home visits at 2, 6 and 9 months and the parents completed questionnaire. Parents in the intervention group reported less screen time and less aggressive behaviour than those in the control group but there were no differences in BMI z scores. This study shows that a preschool-based intervention can lead to reductions in young children's television/video viewing. © 2014 John Wiley & Sons Ltd.

  10. Replicating Reducing the Risk: 12-Month Impacts of a Cluster Randomized Controlled Trial

    Science.gov (United States)

    Blocklin, Michelle; Layzer, Jean; Price, Cristofer; Juras, Randall; Freiman, Lesley

    2016-01-01

    Objectives. To test the effectiveness of Reducing the Risk, an evidence-based sexual health curriculum designed to help prevent adolescent pregnancy and sexually transmitted infections, on youth sexual behavior and intermediate outcomes thought to lead to these behaviors. Methods. Classes within schools in St. Louis, Missouri; Austin, Texas; and San Diego, California; were randomly assigned to receive Reducing the Risk or “business as usual.” Youths completed Web-based surveys at baseline (preintervention, August 2012–January 2014) and 12 months later (August 2013–January 2015). Intent-to-treat analyses were conducted across sites; we tested for differences in impacts between sites and other subgroups. Results. The program had no overall impact on sexual behaviors. However, at 1 site, program participants were significantly less likely to have engaged in recent sexual intercourse than were control group members. There were positive overall impacts on intermediate outcomes (e.g., knowledge, attitudes). Conclusions. After 12 months, Reducing the Risk was unsuccessful at changing sexual behaviors. Other results were mixed, but promising evidence (e.g., behavioral impacts at 1 site, impacts on intermediate outcomes) suggests potential for more widespread behavioral impacts over a longer term. PMID:27689492

  11. Thresholds of a bunched beam longitudinal instability in proton synchrotrons

    International Nuclear Information System (INIS)

    Balbekov, V.I.; Ivanov, S.V.

    1986-01-01

    The formulas and graphs for calculating instability thresholds arising during the interaction of a bunched proton beam with narrow-band resonator are given. The instabilities of three types with oscillations of a definite multipolarity, oscillations of some bound multipoles and with microwave oscillations arising as a result of addition of a great number of multipoles. The analysis of the above data shows that the increase of oscillations nonlinearity is accompanied by the growth of instability threshold only in the zone of separated and weakly bound multipoles. The increase of spread of synchrotron frequencies reduces the zone separated multipoles owing to which the microwave bunch instability can be caused by more and more low-frequency resonators. In the microwave zone practically there is no stabilizing effect of synchrotron frequencies spread. The instability threshold of the bunched beam now - where exceeds the microwave level

  12. Intravenous hydrocortisone premedication reduces antibodies to infliximab in Crohn's disease: a randomized controlled trial.

    Science.gov (United States)

    Farrell, Richard J; Alsahli, Mazen; Jeen, Yoon-Tae; Falchuk, Kenneth R; Peppercorn, Mark A; Michetti, Pierre

    2003-04-01

    We assessed the relationship between antibodies to infliximab (ATI) and the loss of response postinfliximab, infusion reactions and, in a randomized trial, investigated whether intravenous hydrocortisone premedication can reduce ATI. Initially, we prospectively evaluated clinical response, adverse events, and ATI levels in 53 consecutive patients with Crohn's disease who received 199 infliximab (5 mg/kg) infusions. Subsequently, 80 patients with Crohn's disease were randomized to intravenous hydrocortisone 200 mg or placebo immediately before their first and subsequent infliximab infusions. The primary endpoint was reduction in median ATI levels at week 16. Analysis was by intention to treat. Nineteen of our initial 53 patients (36%) developed ATI, including all 7 patients with serious infusion reactions (median ATI level, 19.6 microg/mL). Eleven of 15 patients (73%) who lost their initial response were ATI positive compared with none of 21 continuous responders, (8.9 vs. 0.7 microg/mL, P < 0.0001). Administering a second infusion within 8 weeks of the first (OR, 0.13; 95% CI, 0.03-0.5; P = 0.0007) or concurrent immunosuppressants (OR, 0.19; 95% CI, 0.04-1.03; P = 0.007) significantly reduced ATI formation. In the placebo-controlled trial, ATI levels were lower at week 16 among hydrocortisone-treated patients (1.6 vs. 3.4 microg/mL, P = 0.02), and 26% of hydrocortisone-treated patients developed ATI compared with 42% of placebo-treated patients, P = 0.06. Loss of initial response and infusion reactions post-infliximab is strongly related to ATI formation and level. Administering a second infusion within 8 weeks of the first and concurrent immunosuppressant therapy significantly reduce ATI formation. Intravenous hydrocortisone premedication significantly reduces ATI levels but does not eliminate ATI formation or infusion reactions.

  13. Reducing intrusive traumatic memories after emergency caesarean section: A proof-of-principle randomized controlled study.

    Science.gov (United States)

    Horsch, Antje; Vial, Yvan; Favrod, Céline; Harari, Mathilde Morisod; Blackwell, Simon E; Watson, Peter; Iyadurai, Lalitha; Bonsall, Michael B; Holmes, Emily A

    2017-07-01

    Preventative psychological interventions to aid women after traumatic childbirth are needed. This proof-of-principle randomized controlled study evaluated whether the number of intrusive traumatic memories mothers experience after emergency caesarean section (ECS) could be reduced by a brief cognitive intervention. 56 women after ECS were randomized to one of two parallel groups in a 1:1 ratio: intervention (usual care plus cognitive task procedure) or control (usual care). The intervention group engaged in a visuospatial task (computer-game 'Tetris' via a handheld gaming device) for 15 min within six hours following their ECS. The primary outcome was the number of intrusive traumatic memories related to the ECS recorded in a diary for the week post-ECS. As predicted, compared with controls, the intervention group reported fewer intrusive traumatic memories (M = 4.77, SD = 10.71 vs. M = 9.22, SD = 10.69, d = 0.647 [95% CI: 0.106, 1.182]) over 1 week (intention-to-treat analyses, primary outcome). There was a trend towards reduced acute stress re-experiencing symptoms (d = 0.503 [95% CI: -0.032, 1.033]) after 1 week (intention-to-treat analyses). Times series analysis on daily intrusions data confirmed the predicted difference between groups. 72% of women rated the intervention "rather" to "extremely" acceptable. This represents a first step in the development of an early (and potentially universal) intervention to prevent postnatal posttraumatic stress symptoms that may benefit both mother and child. ClinicalTrials.gov, www.clinicaltrials.gov, NCT02502513. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  14. Reduced Self-Control after 3 Months of Imprisonment; A Pilot Study

    Directory of Open Access Journals (Sweden)

    Jesse Meijers

    2018-02-01

    Full Text Available Background: Prison can be characterized as an impoverished environment encouraging a sedentary lifestyle with limited autonomy and social interaction, which may negatively affect self-control and executive function. Here, we aim to study the effects of imprisonment on self-control and executive functions, and we report the change in neuropsychological outcome after 3 months of imprisonment.Materials and Methods: Participants were 37 male inmates in a remand prison in Amsterdam, Netherlands, who completed six tests of a computerized neuropsychological test battery (the Cambridge Automated Neuropsychological Test Battery in the first week of arrival. Participants were retested after 3 months of imprisonment. Change in performance was tested using the Wilcoxon Signed-Rank test.Results: After 3 months of imprisonment, risk taking significantly increased (measured as an increase in the proportion of available points used for betting and attention significantly deteriorated (measured as increased variability in reaction times on a sustained attention task, with large to medium effect sizes. In contrast, planning significantly improved (measured with a task analog to the Tower of London with a medium effect size.Discussion: Our study suggests that 3 months of imprisonment in an impoverished environment may lead to reduced self-control, measured as increased risk taking and reduced attentional performance. This is a significant and societally relevant finding, as released prisoners may be less capable of living a lawful life than they were prior to their imprisonment, and may be more prone to impulsive risk-taking behavior. In other words, the impoverished environment may contribute to an enhanced risk of reoffending.

  15. The Efficacy of Casual Videogame Play in Reducing Clinical Depression: A Randomized Controlled Study.

    Science.gov (United States)

    Russoniello, Carmen V; Fish, Matthew; O'Brien, Kevin

    2013-12-01

    Depression is a debilitating illness that is estimated to affect more than 300 million people worldwide. Although there has been some success in treatment of this illness with pharmaceuticals and behavioral techniques like cognitive behavioral therapy, these are often costly and have stigma associated with them. The purpose of this study was to test whether a prescribed regimen of casual videogame (CVG) play could reduce symptoms associated with depression. Participants were screened for depression using the Patient Health Questionnaire-9 (PHQ-9). They were then randomized into the control (n=29) or experimental (n=30) group. Experimental participants were prescribed to play CVGs three times per week (with 24 hours between each session), for 30 minutes, over a 1-month period. Control participants surfed the National Institute of Mental Health's Web page on depression. The instrument used to test the hypothesis was the PHQ-9. Repeated-measures statistical analyses revealed there was a significant interaction of group and time, supporting the hypothesis that the groups would be different after the intervention. Moreover, when data were compared using tests of within-subjects contrasts between baseline (Time 1) and the end of the 1-month study (Time 3), we found significant decreases in depression symptoms in the experimental group. When this was compared with the control group changes, the results were still significant. We found that a prescribed regimen of playing CVGs significantly reduced symptoms of clinical depression as measured by the PHQ-9. Clinicians should consider these low-cost CVGs as a possible intervention to address psychological and somatic symptoms associated with depression.

  16. Instability of self-esteem, self-confidence, self-liking, self-control, self-competence and perfectionism: associations with oral health status and oral health-related behaviours.

    Science.gov (United States)

    Dumitrescu, A L; Zetu, L; Teslaru, S

    2012-02-01

    Our aim was to explore whether instability of self-esteem, self-confidence, self-liking, self-control, self-competence and perfectionism each has an independent contribution to the self-rated oral health and oral health-related behaviours. A cross-sectional study design was used. Data were collected between November 2008 and May 2009. The sample consisted of 205 Romanian adults (mean age: 29.84 years; 65.2% women; 40% married) who were a random population drawn consecutively from the registry file of two private dental practices in the Iasi area. The questionnaire included information about demographic, psychological, self-reported oral health and oral health-related behaviour items. The comparison of participants who never flossed their teeth with those who flossed everyday showed statistically significant lower levels of self-confidence (P self-liking (P = 0.001), self-competence (P self-control (P self-competence were scored in persons who used weekly mouthrinses comparing with never users (P = 0.012). Also patients who visited the dentist mainly when treatment is needed or when pain presented lower levels of self-competence and self-control comparing with those who visited the dentist mainly for check-up or for tooth cleaning and scaling (P self-competence and perfectionism variables. Our study showed that instability of self-esteem, self-confidence, self-competence, self-liking, self-control and perfectionism was associated not only with self-rated dental health but also with oral health behaviours. Understanding the psychological factors associated with oral hygiene can further the development and improvement in therapeutic strategies to be used in oral health-improving programs, as well as of programs aimed at prevention and education. © 2011 John Wiley & Sons A/S.

  17. Aromatherapy for reducing colonoscopy related procedural anxiety and physiological parameters: a randomized controlled study.

    Science.gov (United States)

    Hu, Pei-Hsin; Peng, Yen-Chun; Lin, Yu-Ting; Chang, Chi-Sen; Ou, Ming-Chiu

    2010-01-01

    Colonoscopy is generally tolerated, some patients regarding the procedure as unpleasant and painful and generally performed with the patient sedated and receiving analgesics. The effect of sedation and analgesia for colonoscopy is limited. Aromatherapy is also applied to gastrointestinal endoscopy to reduce procedural anxiety. There is lack of information about aromatherapy specific for colonoscopy. In this study, we aimed to performed a randomized controlled study to investigate the effect of aromatherapy on relieve anxiety, stress and physiological parameters of colonoscopy. A randomized controlled trail was carried out and collected in 2009 and 2010. The participants were randomized in two groups. Aromatherapy was then carried out by inhalation of Sunflower oil (control group) and Neroli oil (Experimental group). The anxiety index was evaluated by State Trait Anxiety Inventory-state (STAI-S) score before aromatherapy and after colonoscopy as well as the pain index for post-procedural by visual analogue scale (VAS). Physiological indicators, such as blood pressure (systolic and diastolic blood pressure), heart rate and respiratory rate were evaluated before and after aromatherapy. Participates in this study were 27 subjects, 13 in control group and 14 in Neroli group with average age 52.26 +/- 17.79 years. There was no significance of procedural anxiety by STAI-S score and procedural pain by VAS. The physiological parameters showed a significant lower pre- and post-procedural systolic blood pressure in Neroli group than control group. Aromatic care for colonoscopy, although with no significant effect on procedural anxiety, is an inexpensive, effective and safe pre-procedural technique that could decrease systolic blood pressure.

  18. A Reduced-Order Controller Considering High-Order Modal Information of High-Rise Buildings for AMD Control System with Time-Delay

    Directory of Open Access Journals (Sweden)

    Zuo-Hua Li

    2017-01-01

    Full Text Available Time-delays of control force calculation, data acquisition, and actuator response will degrade the performance of Active Mass Damper (AMD control systems. To reduce the influence, model reduction method is used to deal with the original controlled structure. However, during the procedure, the related hierarchy information of small eigenvalues will be directly discorded. As a result, the reduced-order model ignores the information of high-order mode, which will reduce the design accuracy of an AMD control system. In this paper, a new reduced-order controller based on the improved Balanced Truncation (BT method is designed to reduce the calculation time and to retain the abandoned high-order modal information. It includes high-order natural frequency, damping ratio, and vibration modal information of the original structure. Then, a control gain design method based on Guaranteed Cost Control (GCC algorithm is presented to eliminate the adverse effects of data acquisition and actuator response time-delays in the design process of the reduced-order controller. To verify its effectiveness, the proposed methodology is applied to a numerical example of a ten-storey frame and an experiment of a single-span four-storey steel frame. Both numerical and experimental results demonstrate that the reduced-order controller with GCC algorithm has an excellent control effect; meanwhile it can compensate time-delays effectively.

  19. Clinical strategies for complete denture rehabilitation in a patient with Parkinson disease and reduced neuromuscular control.

    Science.gov (United States)

    Haralur, Satheesh B

    2015-01-01

    The dentist has a large role in geriatric health care for the ever increasing elder population with associated physical and neurological disorders. The Parkinson disease is progressive neurological disorder with resting tremor, bradykinesia, akinesia, and postural instability. The psychological components of disease include depression, anxiety, and cognitive deficiency. Poor oral hygiene, increased susceptibility for dental caries, and periodontal diseases predispose them to early edentulism. The number of Parkinson affected patients visiting dental clinic seeking complete denture is growing. This case report explains the steps involved in the complete denture rehabilitation of Parkinson patient. The effective prosthesis will help in alleviating functional, aesthetic, and psychological disabilities of the patient.

  20. Clinical Strategies for Complete Denture Rehabilitation in a Patient with Parkinson Disease and Reduced Neuromuscular Control

    Directory of Open Access Journals (Sweden)

    Satheesh B. Haralur

    2015-01-01

    Full Text Available The dentist has a large role in geriatric health care for the ever increasing elder population with associated physical and neurological disorders. The Parkinson disease is progressive neurological disorder with resting tremor, bradykinesia, akinesia, and postural instability. The psychological components of disease include depression, anxiety, and cognitive deficiency. Poor oral hygiene, increased susceptibility for dental caries, and periodontal diseases predispose them to early edentulism. The number of Parkinson affected patients visiting dental clinic seeking complete denture is growing. This case report explains the steps involved in the complete denture rehabilitation of Parkinson patient. The effective prosthesis will help in alleviating functional, aesthetic, and psychological disabilities of the patient.

  1. Reduced-graphene-oxide supported tantalum-based electrocatalysts: Controlled nitrogen doping and oxygen reduction reaction

    Science.gov (United States)

    Yang, Xiaoyun; Mo, Qijie; Guo, Yulin; Chen, Nana; Gao, Qingsheng

    2018-03-01

    Controlled N-doping is feasible to engineer the surface stoichiometry and the electronic configuration of metal-oxide electrocatalysts toward efficient oxygen reduction reactions (ORR). Taking reduced graphene oxide supported tantalum-oxides (TaOx/RGO) for example, this work illustrated the controlled N-doping in both metal-oxides and carbon supports, and the contribution to the improved ORR activity. The active N-doped TaOx/RGO electrocatalysts were fabricated via SiO2-assisted pyrolysis, in which the amount and kind of N-doping were tailored toward efficient electrocatalysis. The optimal nanocomposites showed a quite positive half-wave potential (0.80 V vs. RHE), the excellent long-term stability, and the outstanding tolerance to methanol crossing. The improvement in ORR was reasonably attributed to the synergy between N-doped TaOx and N-doped RGO. Elucidating the importance of controlled N-doping for electrocatalysis, this work will open up new opportunities to explore noble-metal-free materials for renewable energy applications.

  2. Edaravone Reduces Hyperperfusion-Related Neurological Deficits in Adult Moyamoya Disease: Historical Control Study.

    Science.gov (United States)

    Uchino, Haruto; Nakayama, Naoki; Kazumata, Ken; Kuroda, Satoshi; Houkin, Kiyohiro

    2016-07-01

    Postoperative hyperperfusion-related transient neurological deficits (TNDs) are frequently observed in adult patients with moyamoya disease who undergo direct bypass procedures. The present study evaluated the effect of the free radical scavenger edaravone on postoperative hyperperfusion in adult moyamoya disease. This study included 92 hemispheres in 72 adult patients who underwent direct bypass for moyamoya disease. Serial measurements of cerebral blood flow were conducted immediately after surgery and on postoperative days 2 and 7. In 40 hemispheres for 36 patients, edaravone (60 mg/d) was administered from the day of surgery to postsurgical day 7. The incidence of postoperative hyperperfusion and associated TNDs were compared with a control group that included 52 hemispheres in 36 patients. Radiological hyperperfusion was observed in 28 of 40 (70.0%) and 39 of 52 (75.0%) hemispheres in the edaravone and control groups, respectively (P=0.30). Hyperperfusion-related TND incidences were significantly lower in the edaravone group compared with the control group (12.5% versus 32.7%; P=0.024). Multivariate analysis demonstrated that edaravone administration (P=0.009) and left-sided surgery (P=0.037) were significantly correlated with hyperperfusion-related TNDs (odds ratios, 0.3 and 4.2, respectively). Perioperative administration of edaravone reduced the incidence of hyperperfusion-related TNDs after direct bypass procedures in adult patients with moyamoya disease. © 2016 American Heart Association, Inc.

  3. Proximal forearm extensor muscle strain is reduced when driving nails using a shock-controlled hammer.

    Science.gov (United States)

    Buchanan, Kimberly A; Maza, Maria; Pérez-Vázquez, Carlos E; Yen, Thomas Y; Kijowski, Richard; Liu, Fang; Radwin, Robert G

    2016-10-01

    Repetitive hammer use has been associated with strain and musculoskeletal injuries. This study investigated if using a shock-control hammer reduces forearm muscle strain by observing adverse physiological responses (i.e. inflammation and localized edema) after use. Three matched framing hammers were studied, including a wood-handle, steel-handle, and shock-control hammer. Fifty volunteers were randomly assigned to use one of these hammers at a fatiguing pace of one strike every second, to seat 20 nails in a wood beam. Magnetic resonance imaging was used to scan the forearm muscles for inflammation before the task, immediately after hammering, and one to two days after. Electromyogram signals were measured to estimate grip exertions and localized muscle fatigue. High-speed video was used to calculate the energy of nail strikes. While estimated grip force was similar across the three hammers, the shock-control hammer had 40% greater kinetic energy upon impact and markedly less proximal extensor muscle edema than the wood-handle and steel-handle hammers, immediately after use (phandle shock can mitigate strain in proximal forearm extensor muscles. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Neuromuscular training reduces lower limb injuries in elite female basketball players. A cluster randomized controlled trial.

    Science.gov (United States)

    Bonato, M; Benis, R; La Torre, A

    2018-04-01

    The study was a two-armed, parallel group, cluster randomized controlled trial in which 15 teams (160 players) were assigned to either an experimental group (EG, 8 teams n = 86), which warmed-up with bodyweight neuromuscular exercises, or a control group (CG, 7 teams, n = 74) that performed standard tactical-technical exercises before training. All injuries during the 2015-2016 regular season were counted. Epidemiologic incidence proportion and incidence rate were also calculated. Countermovement jump (CMJ) and composite Y-Excursion Balance test (YBT) were used to assess lower limb strength and postural control. A total of 111 injuries were recorded. Chi-square test detected statistically significant differences between EG and CG (32 vs 79, P = .006). Significant differences in the injuries sustained in the EG (21 vs 11, P = .024) and CG (52 vs 27, P = .0001) during training and matches, respectively, were observed. Significant differences in post-intervention injuries were observed between in EG and CG during training (21 vs 52, P training into warm-up routines reduced the incidence of serious lower limb injuries in elite female basketball players. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  5. Water Chemistry Control in Reducing Corrosion and Radiation Exposure at PWR Reactor

    International Nuclear Information System (INIS)

    Febrianto

    2006-01-01

    Water chemistry control plays an important role in relation to plant availability, reliability and occupational radiation exposures. Radiation exposures of nuclear plant workers are determined by the radiation rate dose and by the amount maintenance and repair work time Water chemistry has always been, from beginning of operation of power Pressurized Water Reactor, an important factor in determining the integrity of reactor components, fuel cladding integrity and minimize out of core radiation exposures. For primary system, the parameters to control the quality of water chemistry have been subject to change in time. Reactor water coolant pH need to be optimally controlled and be operated in range pH 6.9 to 7.4. At pH lower than 6.9, cause increasing the radiation exposure level and increasing coolant water pH higher than 7.4 will decrease radiation exposure level but increasing risk to fuel cladding and steam generator tube. Since beginning 90 decade, PWR water coolant pH tend to be operated at pH 7.4. This paper will discuss concerning water chemistry development in reducing corrosion and radiation exposure dose in PWR reactor. (author)

  6. Neurofeedback reduces overeating episodes in female restrained eaters: a randomized controlled pilot-study.

    Science.gov (United States)

    Schmidt, Jennifer; Martin, Alexandra

    2015-12-01

    Overeating episodes, despite of intentions to control weight, are a common problem among women. Recurring episodes of overeating and dietary failure have been reported to result in higher Body Mass Indexes and to induce severe distress even in non-clinical groups. Based on findings from physiological research on eating behavior and craving, as well as previous biofeedback studies, we derived a cue exposure based EEG neurofeedback protocol to target overeating episodes. The treatment was evaluated in a randomized controlled trial, comparing a neurofeedback group (NFG; n = 14) with a waiting list control group (WLG; n = 13) in a sub-clinical sample of female restrained eaters. At post-treatment, the number of weekly overeating episodes and subsequent distress were significantly reduced in the NFG compared to the WLG (p  .50). In a 3 month follow-up, effects in the NFG remained stable. As secondary outcomes, perceived dieting success was enhanced after the treatment. At follow-up, additional beneficial effects on trait food craving were observed. Altogether, we found preliminary evidence for the cue exposure neurofeedback against overeating episodes in female restrained eaters, although specific effects and underlying mechanisms still have to be explored in future research.

  7. Instabilities excited by head-on collisions of two relativistic electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Kou Shu-Ying

    1982-02-01

    In this paper, we studied the instabilities excited by head-on collision of two relativistic electron beams in transporting, taking account of the magnetic field B/sub 0/ and the thermal pressure delp of the beams. The conditions under which the instabilities occur and the growth rate of instabilities are obtained. The results show that these instabilities can be excited or inhibited by controlling the velocity of the beams.

  8. Instability of expanding bacterial droplets.

    Science.gov (United States)

    Sokolov, Andrey; Rubio, Leonardo Dominguez; Brady, John F; Aranson, Igor S

    2018-04-03

    Suspensions of motile bacteria or synthetic microswimmers, termed active matter, manifest a remarkable propensity for self-organization, and formation of large-scale coherent structures. Most active matter research deals with almost homogeneous in space systems and little is known about the dynamics of strongly heterogeneous active matter. Here we report on experimental and theoretical studies on the expansion of highly concentrated bacterial droplets into an ambient bacteria-free fluid. The droplet is formed beneath a rapidly rotating solid macroscopic particle inserted in the suspension. We observe vigorous instability of the droplet reminiscent of a violent explosion. The phenomenon is explained in terms of continuum first-principle theory based on the swim pressure concept. Our findings provide insights into the dynamics of active matter with strong density gradients and significantly expand the scope of experimental and analytic tools for control and manipulation of active systems.

  9. Investigation of natural circulation instability and transients in passively safe novel modular reactor

    Science.gov (United States)

    Shi, Shanbin

    The Purdue Novel Modular Reactor (NMR) is a new type small modular reactor (SMR) that belongs to the design of boiling water reactor (BWR). Specifically, the NMR is one third the height and area of a conventional BWR reactor pressure vessel (RPV) with an electric output of 50 MWe. The fuel cycle length of the NMR-50 is extended up to 10 years due to optimized neutronics design. The NMR-50 is designed with double passive engineering safety system. However, natural circulation BWRs (NCBWR) could experience certain operational difficulties due to flow instabilities that occur at low pressure and low power conditions. Static instabilities (i.e. flow excursion (Ledinegg) instability and flow pattern transition instability) and dynamic instabilities (i.e. density wave instability and flashing/condensation instability) pose a significant challenge in two-phase natural circulation systems. In order to experimentally study the natural circulation flow instability, a proper scaling methodology is needed to build a reduced-size test facility. The scaling analysis of the NMR uses a three-level scaling method, which was developed and applied for the design of the Purdue Multi-dimensional Integral Test Assembly (PUMA). Scaling criteria is derived from dimensionless field equations and constitutive equations. The scaling process is validated by the RELAP5 analysis for both steady state and startup transients. A new well-scaled natural circulation test facility is designed and constructed based on the scaling analysis of the NMR-50. The experimental facility is installed with different equipment to measure various thermal-hydraulic parameters such as pressure, temperature, mass flow rate and void fraction. Characterization tests are performed before the startup transient tests and quasi-steady tests to determine the loop flow resistance. The controlling system and data acquisition system are programmed with LabVIEW to realize the real-time control and data storage. The thermal

  10. Beam--plasma instabilities and the beam--plasma discharge

    International Nuclear Information System (INIS)

    Kellogg, P.J.; Boswell, R.W.

    1986-01-01

    Using a new electron gun, a number of measurements bearing on the generation of beam--plasma discharge (BPD) in WOMBAT (waves on magnetized beams and turbulence) [R. W. Boswell and P. J. Kellogg, Geophys. Res. Lett. 10, 565 (1983)] have been made. A beam--plasma discharge is an rf discharge in which the rf fields are provided by instabilities [W. D. Getty and L. D. Smullin, J. Appl. Phys. 34, 3421 (1963)]. The new gun has a narrower divergence angle than the old, and comparison of the BPD thresholds for the two guns verifies that the BPD ignition current is proportional to the cross-sectional area of the plasma. The high-frequency instabilities, precursors to the BPD, are identified with the two Trivelpiece--Gould modes [A. W. Trivelpiece and R. W. Gould, J. Appl. Phys. 30, 1784 (1959)]. Which frequency appears depends on the neutral pressure. The measured frequencies are not consistent with the simple interpretation of the lower frequency as a Cerenkov resonance with the low-Trivelpiece--Gould mode; it must be a cyclotron resonance. As is generally true in such beam--plasma interaction experiments, strong low-frequency waves appear at currents far below those necessary for BPD ignition. These low-frequency waves are shown to control the onset of the high-frequency precursors to the BPD. A mechanism for this control is suggested, which involves the conversion of a convective instability to an absolute one by trapping of the unstable waves in the density perturbations of the low-frequency waves. This process greatly reduces the current necessary for BPD ignition

  11. Instability of warped discs

    Science.gov (United States)

    Doǧan, S.; Nixon, C. J.; King, A. R.; Pringle, J. E.

    2018-05-01

    Accretion discs are generally warped. If a warp in a disc is too large, the disc can `break' apart into two or more distinct planes, with only tenuous connections between them. Further, if an initially planar disc is subject to a strong differential precession, then it can be torn apart into discrete annuli that precess effectively independently. In previous investigations, torque-balance formulae have been used to predict where and when the disc breaks into distinct parts. In this work, focusing on discs with Keplerian rotation and where the shearing motions driving the radial communication of the warp are damped locally by turbulence (the `diffusive' regime), we investigate the stability of warped discs to determine the precise criterion for an isolated warped disc to break. We find and solve the dispersion relation, which, in general, yields three roots. We provide a comprehensive analysis of this viscous-warp instability and the emergent growth rates and their dependence on disc parameters. The physics of the instability can be understood as a combination of (1) a term that would generally encapsulate the classical Lightman-Eardley instability in planar discs (given by ∂(νΣ)/∂Σ < 0) but is here modified by the warp to include ∂(ν1|ψ|)/∂|ψ| < 0, and (2) a similar condition acting on the diffusion of the warp amplitude given in simplified form by ∂(ν2|ψ|)/∂|ψ| < 0. We discuss our findings in the context of discs with an imposed precession, and comment on the implications for different astrophysical systems.

  12. Evaporation and Antievaporation Instabilities

    Directory of Open Access Journals (Sweden)

    Andrea Addazi

    2017-10-01

    Full Text Available We review (antievaporation phenomena within the context of quantum gravity and extended theories of gravity. The (antievaporation effect is an instability of the black hole horizon discovered in many different scenarios: quantum dilaton-gravity, f ( R -gravity, f ( T -gravity, string-inspired black holes, and brane-world cosmology. Evaporating and antievaporating black holes seem to have completely different thermodynamical features compared to standard semiclassical black holes. The purpose of this review is to provide an introduction to conceptual and technical aspects of (antievaporation effects, while discussing problems that are still open.

  13. Possibilities for reducing control and speeding up procedures in the judicial control, according to the Federal Immission Control Act, section 6, of licences granted

    International Nuclear Information System (INIS)

    Schwab, J.

    1986-01-01

    On evaluating court rulings and literature it is seen that there is far-reaching disagreement in dealing with the density of administrative control in immission protection. Further problems consist in the fact that law-suits take extremely long to conclude and that the courts of administration are faced with an immense load of work. This thesis therefore aims to point out ways and means in accordance with democratic practices to reduce the difficulties now existing. Ways are sought to reduce control via the material immission protection regulations and via administrative regulations. A comparison with American legal practice shows that courts primarily supervise the administrative procedure and develop its rules further. That practice lies within the limits of the theory of the scope of evaluation. (HSCH) [de

  14. Comparing clinical efficacy of Symbicort versus Pulmicort in reducing asthma symptom and improving its control

    Directory of Open Access Journals (Sweden)

    Mohammad Emami

    2014-01-01

    Full Text Available Background: Recently, higher efficacy of the combination of long-acting beta2-adrenoceptor agonist and inhaled corticosteroids on controlling asthma symptoms has been hypothesized. This study aimed to examine the clinical effects of the combination of Budesonide with formoterol (Symbicort and Budesonide (Pulmicort alone in persistent asthma. Materials and Methods: In a randomized double-blinded clinical trial, 76 patients with definite diagnosis of moderate-to-severe asthma were randomized to receive Pulmicort 180 mcg/inhalation two puffs twice daily, or receive Symbicort 80/4.5 mg/inhalation two puffs twice daily, or receive Symbicort 160/4.5 mg/inhalation two puffs twice daily for 3 months. All participants were initially evaluated by spirometry for assessing respiratory parameters and also the level of asthma control was assessed by Asthma Control Test (ACT. Results: More significant improvement in spirometry parameters, including forced expiratory volume in 1 second (FEV1, forced vital capacity (FVC, FEV1/FVC ratio, as well as in peak expiratory flow (PEF in both groups of Symbicort with the regimens 80/4.5 mg/inhalation or 160/4.5 mg/inhalation 2 puffs twice daily compared with Pulmicort group, ACT score was significantly improved in Symbicort group with the regimens 160/4.5 mg/inhalation compared with both Symbicort groups with lower dosage and Pulmicort group . Response to treatment in PEF parameter and also in ACT level was significantly more in those who received Symbicort with the regimens 160/4.5 mg/inhalation compared with other two interventional groups adjusted for gender and age. Conclusion: Symbicort with the regimens 160/4.5 mg/inhalation has higher efficacy in reducing asthma symptom and improving its control compared with low doses of this drug and with Pulmicort.

  15. Physiotherapy programme reduces fatigue in patients with advanced cancer receiving palliative care: randomized controlled trial.

    Science.gov (United States)

    Pyszora, Anna; Budzyński, Jacek; Wójcik, Agnieszka; Prokop, Anna; Krajnik, Małgorzata

    2017-09-01

    Cancer-related fatigue (CRF) is a common and relevant symptom in patients with advanced cancer that significantly decreases their quality of life. The aim of this study was to evaluate the effect of a physiotherapy programme on CRF and other symptoms in patients diagnosed with advanced cancer. The study was designed as a randomized controlled trial. Sixty patients diagnosed with advanced cancer receiving palliative care were randomized into two groups: the treatment group (n = 30) and the control group (n = 30). The therapy took place three times a week for 2 weeks. The 30-min physiotherapy session included active exercises, myofascial release and proprioceptive neuromuscular facilitation (PNF) techniques. The control group did not exercise. The outcomes included Brief Fatigue Inventory (BFI), Edmonton Symptom Assessment Scale (ESAS) and satisfaction scores. The exercise programme caused a significant reduction in fatigue scores (BFI) in terms of severity of fatigue and its impact on daily functioning. In the control group, no significant changes in the BFI were observed. Moreover, the physiotherapy programme improved patients' general well-being and reduced the intensity of coexisting symptoms such as pain, drowsiness, lack of appetite and depression. The analysis of satisfaction scores showed that it was also positively evaluated by patients. The physiotherapy programme, which included active exercises, myofascial release and PNF techniques, had beneficial effects on CRF and other symptoms in patients with advanced cancer who received palliative care. The results of the study suggest that physiotherapy is a safe and effective method of CRF management.

  16. Cognitive bias modification versus CBT in reducing adolescent social anxiety: a randomized controlled trial.

    Science.gov (United States)

    Sportel, B Esther; de Hullu, Eva; de Jong, Peter J; Nauta, Maaike H

    2013-01-01

    Social anxiety is a common mental disorder among adolescents and is associated with detrimental long term outcomes. Therefore, this study investigated the efficacy of two possible early interventions for adolescent social anxiety and test anxiety. An internet-based cognitive bias modification (CBM; n = 86) was compared to a school-based cognitive behavioral group training (CBT; n = 84) and a control group (n = 70) in reducing symptoms of social and test anxiety in high socially and/or test anxious adolescents aged 13-15 years. Participants (n = 240) were randomized at school level over the three conditions. CBM consisted of a 20-session at home internet-delivered training; CBT was a 10-session at school group training with homework assignments; the control group received no training. Participants were assessed before and after the intervention and at 6 and 12 month follow-up. At 6 month follow-up CBT resulted in lower social anxiety than the control condition, while for CBM, this effect was only trend-significant. At 12 month follow-up this initial benefit was no longer present. Test anxiety decreased more in the CBT condition relative to the control condition in both short and long term. Interestingly, in the long term, participants in the CBM condition improved more with regard to automatic threat-related associations than both other conditions. The results indicate that the interventions resulted in a faster decline of social anxiety symptoms, whereas the eventual end point of social anxiety was not affected. Test anxiety was influenced in the long term by the CBT intervention, and CBM lead to increased positive automatic threat-related associations. TrialRegister.nl NTR965.

  17. LA sprouts randomized controlled nutrition and gardening program reduces obesity and metabolic risk in Latino youth.

    Science.gov (United States)

    Gatto, Nicole M; Martinez, Lauren C; Spruijt-Metz, Donna; Davis, Jaimie N

    2015-06-01

    To assess the effects of a 12-week gardening, nutrition, and cooking intervention ("LA Sprouts") on dietary intake, obesity parameters, and metabolic disease risk among low-income, primarily Hispanic/Latino youth in Los Angeles. The randomized controlled trial involved four elementary schools [two schools randomized to intervention (172 third-through fifth-grade students); two schools randomized to control (147 third-through fifth-grade students)]. Classes were taught in 90-minute sessions once a week to each grade level for 12 weeks. Data collected at pre- and postintervention included dietary intake via food frequency questionnaire (FFQ), anthropometric measures [BMI, waist circumference (WC)], body fat, and fasting blood samples. LA Sprouts participants had significantly greater reductions in BMI z-scores (0.1-vs. 0.04-point decrease, respectively; P = 0.01) and WC (-1.2 cm vs. no change; P < 0.001). Fewer LA Sprouts participants had the metabolic syndrome (MetSyn) after the intervention than before, while the number of controls with MetSyn increased. LA Sprouts participants had improvements in dietary fiber intake (+3.5% vs. -15.5%; P = 0.04) and less decreases in vegetable intake (-3.6% vs. -26.4%; P = 0.04). Change in fruit intake before and after the intervention did not significantly differ between LA Sprouts and control subjects. LA Sprouts was effective in reducing obesity and metabolic risk. © 2015 The Obesity Society.

  18. Resonant Drag Instabilities in protoplanetary disks: the streaming instability and new, faster-growing instabilities

    Science.gov (United States)

    Squire, Jonathan; Hopkins, Philip F.

    2018-04-01

    We identify and study a number of new, rapidly growing instabilities of dust grains in protoplanetary disks, which may be important for planetesimal formation. The study is based on the recognition that dust-gas mixtures are generically unstable to a Resonant Drag Instability (RDI), whenever the gas, absent dust, supports undamped linear modes. We show that the "streaming instability" is an RDI associated with epicyclic oscillations; this provides simple interpretations for its mechanisms and accurate analytic expressions for its growth rates and fastest-growing wavelengths. We extend this analysis to more general dust streaming motions and other waves, including buoyancy and magnetohydrodynamic oscillations, finding various new instabilities. Most importantly, we identify the disk "settling instability," which occurs as dust settles vertically into the midplane of a rotating disk. For small grains, this instability grows many orders of magnitude faster than the standard streaming instability, with a growth rate that is independent of grain size. Growth timescales for realistic dust-to-gas ratios are comparable to the disk orbital period, and the characteristic wavelengths are more than an order of magnitude larger than the streaming instability (allowing the instability to concentrate larger masses). This suggests that in the process of settling, dust will band into rings then filaments or clumps, potentially seeding dust traps, high-metallicity regions that in turn seed the streaming instability, or even overdensities that coagulate or directly collapse to planetesimals.

  19. Interplay between parametric instabilities in fusion - relevant laser plasmas

    International Nuclear Information System (INIS)

    Huller, St.

    2003-01-01

    The control of parametric instabilities plays an important role in laser fusion. They are driven by the incident laser beams in the underdense plasma surrounding a fusion capsule and hinder the absorption process of incident laser light which is necessary to heat the fusion target. Due to its high intensity and power, the laser light modifies the plasma density dynamically, such that two or more parametric instabilities compete, in particular stimulated Brillouin scattering and the filamentation instability. The complicated interplay between these parametric instabilities is studied in detail by developing an adequate model accompanied by numerical simulations with multidimensional codes. The model is applied to generic and to smoothed laser beams, which are necessary to limit parametric instabilities, with parameters close to experimental conditions. (author)

  20. Shape control of the magnetic iron oxide nanoparticles under different chain length of reducing agents

    International Nuclear Information System (INIS)

    Ngoi, Kuan Hoon; Chia, Chin-Hua; Zakaria, Sarani; Chiu, Wee Siong

    2015-01-01

    We report on the effect of using reducing agents with different chain-length on the synthesis of iron oxide nanoparticles by thermal decomposition of iron (III) acetylacetonate in 1-octadecene. This modification allows us to control the shape of nanoparticles into spherical and cubic iron oxide nanoparticles. The highly monodisperse 14 nm spherical nanoparticles are obtained under 1,2-dodecanediol and average 14 nm edge-length cubic iron oxide nanoparticles are obtained under 1,2-tetradecanediol. The structural characterization such as transmission electron microscope (TEM) and X-ray diffraction (XRD) shows similar properties between two particles with different shapes. The vibrating sample magnetometer (VSM) shows no significant difference between spherical and cubic nanoparticles, which are 36 emu/g and 37 emu/g respectively and superparamagnetic in nature

  1. Shape control of the magnetic iron oxide nanoparticles under different chain length of reducing agents

    Energy Technology Data Exchange (ETDEWEB)

    Ngoi, Kuan Hoon; Chia, Chin-Hua, E-mail: chia@ukm.edu.my; Zakaria, Sarani [School of Applied Physics, Faculty Science and Technology, University Kebangsaan Malaysia 43600 UKM Bangi, Selangor (Malaysia); Chiu, Wee Siong [Low Dimensional Materials Research Centre, Department of Physics, Faculty of Science, University of Malaya, 50603 Lembah Pantai, Kuala Lumpur (Malaysia)

    2015-09-25

    We report on the effect of using reducing agents with different chain-length on the synthesis of iron oxide nanoparticles by thermal decomposition of iron (III) acetylacetonate in 1-octadecene. This modification allows us to control the shape of nanoparticles into spherical and cubic iron oxide nanoparticles. The highly monodisperse 14 nm spherical nanoparticles are obtained under 1,2-dodecanediol and average 14 nm edge-length cubic iron oxide nanoparticles are obtained under 1,2-tetradecanediol. The structural characterization such as transmission electron microscope (TEM) and X-ray diffraction (XRD) shows similar properties between two particles with different shapes. The vibrating sample magnetometer (VSM) shows no significant difference between spherical and cubic nanoparticles, which are 36 emu/g and 37 emu/g respectively and superparamagnetic in nature.

  2. Curvature-Induced Instabilities of Shells

    Science.gov (United States)

    Pezzulla, Matteo; Stoop, Norbert; Steranka, Mark P.; Bade, Abdikhalaq J.; Holmes, Douglas P.

    2018-01-01

    Induced by proteins within the cell membrane or by differential growth, heating, or swelling, spontaneous curvatures can drastically affect the morphology of thin bodies and induce mechanical instabilities. Yet, the interaction of spontaneous curvature and geometric frustration in curved shells remains poorly understood. Via a combination of precision experiments on elastomeric spherical shells, simulations, and theory, we show how a spontaneous curvature induces a rotational symmetry-breaking buckling as well as a snapping instability reminiscent of the Venus fly trap closure mechanism. The instabilities, and their dependence on geometry, are rationalized by reducing the spontaneous curvature to an effective mechanical load. This formulation reveals a combined pressurelike term in the bulk and a torquelike term in the boundary, allowing scaling predictions for the instabilities that are in excellent agreement with experiments and simulations. Moreover, the effective pressure analogy suggests a curvature-induced subcritical buckling in closed shells. We determine the critical buckling curvature via a linear stability analysis that accounts for the combination of residual membrane and bending stresses. The prominent role of geometry in our findings suggests the applicability of the results over a wide range of scales.

  3. Feedback stabilization of plasma instabilities

    International Nuclear Information System (INIS)

    Cap, F.F.

    1977-01-01

    This paper reviews the theoretical and experimental aspects of feedback stabilization. After giving an outline of a general theoretical model for electrostatic instabilities the author provides a theoretical analysis of the suppression of various types of instability. Experiments which have been carried out on the feedback stabilization of various types of plasma instability are reported. An extensive list of references is given. (B.R.H.)

  4. Thermal Shrinkage for Shoulder Instability

    OpenAIRE

    Toth, Alison P.; Warren, Russell F.; Petrigliano, Frank A.; Doward, David A.; Cordasco, Frank A.; Altchek, David W.; O’Brien, Stephen J.

    2010-01-01

    Thermal capsular shrinkage was popular for the treatment of shoulder instability, despite a paucity of outcomes data in the literature defining the indications for this procedure or supporting its long-term efficacy. The purpose of this study was to perform a clinical evaluation of radiofrequency thermal capsular shrinkage for the treatment of shoulder instability, with a minimum 2-year follow-up. From 1999 to 2001, 101 consecutive patients with mild to moderate shoulder instability underwent...

  5. Political Instability and Economic Growth

    OpenAIRE

    Alberto Alesina; Sule Ozler; Nouriel Roubini; Phillip Swagel

    1992-01-01

    This paper investigates the relationship between political instability and per capita GDP growth in a sample of 113 countries for the period 1950-1982. We define ?political instability? as the propensity of a government collapse, and we estimate a model in which political instability and economic growth are jointly determined. The main result of this paper is that in countries and time periods with a high propensity of government collapse, growth is significantly lower than otherwise. This ef...

  6. Efficient control of ultrafast optical nonlinearity of reduced graphene oxide by infrared reduction

    Energy Technology Data Exchange (ETDEWEB)

    Bhattachraya, S.; Maiti, R.; Das, A. C.; Saha, S.; Mondal, S.; Ray, S. K.; Bhaktha, S. N. B.; Datta, P. K., E-mail: pkdatta.iitkgp@gmail.com [Department of Physics, Indian Institute of Technology Kharagpur, Kharagpur 721302 (India)

    2016-07-07

    Simultaneous occurrence of saturable absorption nonlinearity and two-photon absorption nonlinearity in the same medium is well sought for the devices like optical limiter and laser mode-locker. Pristine graphene sheet consisting entirely of sp{sup 2}-hybridized carbon atoms has already been identified having large optical nonlinearity. However, graphene oxide (GO), a precursor of graphene having both sp{sup 2} and sp{sup 3}-hybridized carbon atom, is increasingly attracting cross-discipline researchers for its controllable properties by reduction of oxygen containing groups. In this work, GO has been prepared by modified Hummers method, and it has been further reduced by infrared (IR) radiation. Characterization of reduced graphene oxide (RGO) by means of Raman spectroscopy, X-ray photoelectron spectroscopy, and UV-Visible absorption measurements confirms an efficient reduction with infrared radiation. Here, we report precise control of non-linear optical properties of RGO in femtosecond regime with increased degrees of IR reduction measured by open aperture z-scan technique. Depending on the intensity, both saturable absorption and two-photon absorption effects are found to contribute to the non-linearity of all the samples. Saturation dominates at low intensity (∼127 GW/cm{sup 2}) while two-photon absorption becomes prominent at higher intensities (from 217 GW/cm{sup 2} to 302 GW/cm{sup 2}). The values of two-photon absorption co-efficient (∼0.0022–0.0037 cm/GW for GO, and ∼0.0128–0.0143 cm/GW for RGO) and the saturation intensity (∼57 GW/cm{sup 2} for GO, and ∼194 GW/cm{sup 2} for RGO) increase with increasing reduction, indicating GO and RGO as novel tunable photonic devices. We have also explained the reason of tunable nonlinear optical properties by using amorphous carbon model.

  7. Efficient control of ultrafast optical nonlinearity of reduced graphene oxide by infrared reduction

    International Nuclear Information System (INIS)

    Bhattachraya, S.; Maiti, R.; Das, A. C.; Saha, S.; Mondal, S.; Ray, S. K.; Bhaktha, S. N. B.; Datta, P. K.

    2016-01-01

    Simultaneous occurrence of saturable absorption nonlinearity and two-photon absorption nonlinearity in the same medium is well sought for the devices like optical limiter and laser mode-locker. Pristine graphene sheet consisting entirely of sp"2-hybridized carbon atoms has already been identified having large optical nonlinearity. However, graphene oxide (GO), a precursor of graphene having both sp"2 and sp"3-hybridized carbon atom, is increasingly attracting cross-discipline researchers for its controllable properties by reduction of oxygen containing groups. In this work, GO has been prepared by modified Hummers method, and it has been further reduced by infrared (IR) radiation. Characterization of reduced graphene oxide (RGO) by means of Raman spectroscopy, X-ray photoelectron spectroscopy, and UV-Visible absorption measurements confirms an efficient reduction with infrared radiation. Here, we report precise control of non-linear optical properties of RGO in femtosecond regime with increased degrees of IR reduction measured by open aperture z-scan technique. Depending on the intensity, both saturable absorption and two-photon absorption effects are found to contribute to the non-linearity of all the samples. Saturation dominates at low intensity (∼127 GW/cm"2) while two-photon absorption becomes prominent at higher intensities (from 217 GW/cm"2 to 302 GW/cm"2). The values of two-photon absorption co-efficient (∼0.0022–0.0037 cm/GW for GO, and ∼0.0128–0.0143 cm/GW for RGO) and the saturation intensity (∼57 GW/cm"2 for GO, and ∼194 GW/cm"2 for RGO) increase with increasing reduction, indicating GO and RGO as novel tunable photonic devices. We have also explained the reason of tunable nonlinear optical properties by using amorphous carbon model.

  8. Reduced dopamine transporter binding predates impulse control disorders in Parkinson's disease.

    Science.gov (United States)

    Vriend, Chris; Nordbeck, Anna H; Booij, Jan; van der Werf, Ysbrand D; Pattij, Tommy; Voorn, Pieter; Raijmakers, Pieter; Foncke, Elisabeth M J; van de Giessen, Elsmarieke; Berendse, Henk W; van den Heuvel, Odile A

    2014-06-01

    Impulse control disorders (ICD) are relatively common in Parkinson's disease (PD) and generally are regarded as adverse effects of dopamine replacement therapy, although certain demographic and clinical risk factors are also involved. Previous single-photon emission computed tomography (SPECT) studies showed reduced ventral striatal dopamine transporter binding in Parkinson patients with ICD compared with patients without. Nevertheless, these studies were performed in patients with preexisting impulse control impairments, which impedes clear-cut interpretation of these findings. We retrospectively procured follow-up data from 31 medication-naïve PD patients who underwent dopamine transporter SPECT imaging at baseline and were subsequently treated with dopamine replacement therapy. We used questionnaires and a telephone interview to assess medication status and ICD symptom development during the follow-up period (31.5 ± 12.0 months). Eleven patients developed ICD symptoms during the follow-up period, eight of which were taking dopamine agonists. The PD patients with ICD symptoms at follow-up had higher baseline depressive scores and lower baseline dopamine transporter availability in the right ventral striatum, anterior-dorsal striatum, and posterior putamen compared with PD patients without ICD symptoms. No baseline between-group differences in age and disease stage or duration were found. The ICD symptom severity correlated negatively with baseline dopamine transporter availability in the right ventral and anterior-dorsal striatum. The results of this preliminary study show that reduced striatal dopamine transporter availability predates the development of ICD symptoms after dopamine replacement therapy and may constitute a neurobiological risk factor related to a lower premorbid dopamine transporter availability or a more pronounced dopamine denervation in PD patients susceptible to ICD. © 2014 International Parkinson and Movement Disorder Society.

  9. Smoking reduced in urban restaurants: the effect of Beijing Smoking Control Regulation.

    Science.gov (United States)

    Xiao, Lin; Jiang, Yuan; Liu, Xiurong; Li, Yuqin; Gan, Quan; Liu, Fan

    2017-03-01

    To evaluate the effectiveness of Beijing Smoking Control Regulation, occurrence of smoking in restaurants was compared before and after the law took effect. A cohort study design was used in a randomly selected sample of 176 restaurants in two districts of Beijing. Undercover visits were paid by investigators to the same restaurants at lunch or dinner time 5 months before the law took effect and 1-month after. The occurrence of smoking and presence of no-smoking signs were observed. Much less smoking was observed (14.8%) in restaurants compared to that before the law took effect (40.3%). The drop in smoking occurrence was more evident in open dining areas (from 32.4% to 5.1%) compared to the men's restrooms of the restaurants (23.8% to 18.8%). No intervention from restaurant staff was observed whenever smoking occurred. Posting of no-smoking signage increased considerably after the law came into effect (from 52.6% to 82.4%), but very few no-smoking signs included the symptom hotline number (38.5%) or the amount of penalty (5.6%). The Beijing Smoking Control Regulation achieved one of its intended goals of reducing smoking occurrences in restaurants, but further effort of strengthening implementation is still needed and should focus on boosting compliance with no-smoking sign requirements, reducing smoking in restrooms of the restaurants and mobilising the restaurant staff to intervene in case of violations. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  10. Daily corticosteroids reduce infection-associated relapses in frequently relapsing nephrotic syndrome: a randomized controlled trial.

    Science.gov (United States)

    Gulati, Ashima; Sinha, Aditi; Sreenivas, Vishnubhatla; Math, Aparna; Hari, Pankaj; Bagga, Arvind

    2011-01-01

    Relapses of nephrotic syndrome often follow minor infections, commonly of the upper respiratory tract. Daily administration of maintenance prednisolone during intercurrent infections was examined to determine whether the treatment reduces relapse rates in children with frequently relapsing nephrotic syndrome. In a randomized controlled trial (nonblind, parallel group, tertiary-care hospital), 100 patients with idiopathic, frequently relapsing nephrotic syndrome eligible for therapy with prolonged low-dose, alternate-day prednisolone with or without levamisole were randomized to either receive their usual dose of alternate-day prednisolone daily for 7 days during intercurrent infections (intervention group) or continue alternate-day prednisolone (controls). Primary outcome was assessed by comparing the rates of infection-associated relapses at 12-month follow-up. Secondary outcomes were the frequency of infections and the cumulative amount of prednisolone received in both groups. Patients in the intervention group showed significantly lower infection-associated (rate difference, 0.7 episodes/patient per year; 95% confidence intervals [CI] 0.3, 1.1) and lower total relapse rates (0.9 episodes/patient per year, 95% CI 0.4, 1.4) without increase in steroid toxicity. Poisson regression, adjusted for occurrence of infections, showed that daily administration of prednisolone during infections independently resulted in 59% reduction in frequency of relapses (rate ratio, 0.41; 95% CI 0.3, 0.6). For every six patients receiving this intervention, one showed a reduction of relapse frequency to less than three per year. Daily administration of maintenance doses of prednisolone, during intercurrent infections, significantly reduces relapse rates and the proportion of children with frequently relapsing nephrotic syndrome.

  11. A Communication Intervention to Reduce Resistiveness in Dementia Care: A Cluster Randomized Controlled Trial.

    Science.gov (United States)

    Williams, Kristine N; Perkhounkova, Yelena; Herman, Ruth; Bossen, Ann

    2017-08-01

    Nursing home (NH) residents with dementia exhibit challenging behaviors or resistiveness to care (RTC) that increase staff time, stress, and NH costs. RTC is linked to elderspeak communication. Communication training (Changing Talk [CHAT]) was provided to staff to reduce their use of elderspeak. We hypothesized that CHAT would improve staff communication and subsequently reduce RTC. Thirteen NHs were randomized to intervention and control groups. Dyads (n = 42) including 29 staff and 27 persons with dementia were videorecorded during care before and/or after the intervention and at a 3-month follow-up. Videos were behaviorally coded for (a) staff communication (normal, elderspeak, or silence) and (b) resident behaviors (cooperative or RTC). Linear mixed modeling was used to evaluate training effects. On average, elderspeak declined from 34.6% (SD = 18.7) at baseline by 13.6% points (SD = 20.00) post intervention and 12.2% points (SD = 22.0) at 3-month follow-up. RTC declined from 35.7% (SD = 23.2) by 15.3% points (SD = 32.4) post intervention and 13.4% points (SD = 33.7) at 3 months. Linear mixed modeling determined that change in elderspeak was predicted by the intervention (b = -12.20, p = .028) and baseline elderspeak (b = -0.65, p communication and reduce RTC, providing an effective nonpharmacological intervention to manage behavior and improve the quality of dementia care. No adverse events occurred. © The Author 2016. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  12. Randomized controlled trial of relaxation music to reduce heart rate in patients undergoing cardiac CT.

    Science.gov (United States)

    Ng, Ming Yen; Karimzad, Yasser; Menezes, Ravi J; Wintersperger, Bernd J; Li, Qin; Forero, Julian; Paul, Narinder S; Nguyen, Elsie T

    2016-10-01

    To evaluate the heart rate lowering effect of relaxation music in patients undergoing coronary CT angiography (CCTA), pulmonary vein CT (PVCT) and coronary calcium score CT (CCS). Patients were randomised to a control group (i.e. standard of care protocol) or to a relaxation music group (ie. standard of care protocol with music). The groups were compared for heart rate, radiation dose, image quality and dose of IV metoprolol. Both groups completed State-Trait Anxiety Inventory anxiety questionnaires to assess patient experience. One hundred and ninety-seven patients were recruited (61.9 % males); mean age 56y (19-86 y); 127 CCTA, 17 PVCT, 53 CCS. No significant difference in heart rate, radiation dose, image quality, metoprolol dose and anxiety scores. 86 % of patients enjoyed the music. 90 % of patients in the music group expressed a strong preference to have music for future examinations. The patient cohort demonstrated low anxiety levels prior to CT. Relaxation music in CCTA, PVCT and CCS does not reduce heart rate or IV metoprolol use. Patients showed low levels of anxiety indicating that anxiolytics may not have a significant role in lowering heart rate. Music can be used in cardiac CT to improve patient experience. • Relaxation music does not reduce heart rate in cardiac CT • Relaxation music does not reduce beta-blocker use in cardiac CT • Relaxation music has no effect on cardiac CT image quality • Low levels of anxiety are present in patients prior to cardiac CT • Patients enjoyed the relaxation music and this results in improved patient experience.

  13. Role of echocardiography in reducing shock reversal time in pediatric septic shock: a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Ahmed A. EL-Nawawy

    Full Text Available Abstract Objective: To evaluate the role of echocardiography in reducing shock reversal time in pediatric septic shock. Methods: A prospective study conducted in the pediatric intensive care unit of a tertiary care teaching hospital from September 2013 to May 2016. Ninety septic shock patients were randomized in a 1:1 ratio for comparing the serial echocardiography-guided therapy in the study group with the standard therapy in the control group regarding clinical course, timely treatment, and outcomes. Results: Shock reversal was significantly higher in the study group (89% vs. 67%, with significantly reduced shock reversal time (3.3 vs. 4.5 days. Pediatric intensive care unit stay in the study group was significantly shorter (8 ± 3 vs. 14 ± 10 days. Mortality due to unresolved shock was significantly lower in the study group. Fluid overload was significantly lower in the study group (11% vs. 44%. In the study group, inotropes were used more frequently (89% vs. 67% and initiated earlier (12[0.5-24] vs. 24[6-72] h with lower maximum vasopressor inotrope score (120[30-325] vs. 170[80-395], revealing predominant use of milrinone (62% vs. 22%. Conclusion: Serial echocardiography provided crucial data for early recognition of septic myocardial dysfunction and hypovolemia that was not apparent on clinical assessment, allowing a timely management and resulting in shock reversal time reduction among children with septic shock.

  14. Comparative Analysis of Reduced-Rule Compressed Fuzzy Logic Control and Incremental Conductance MPPT Methods

    Science.gov (United States)

    Kandemir, Ekrem; Borekci, Selim; Cetin, Numan S.

    2018-04-01

    Photovoltaic (PV) power generation has been widely used in recent years, with techniques for increasing the power efficiency representing one of the most important issues. The available maximum power of a PV panel is dependent on environmental conditions such as solar irradiance and temperature. To extract the maximum available power from a PV panel, various maximum-power-point tracking (MPPT) methods are used. In this work, two different MPPT methods were implemented for a 150-W PV panel. The first method, known as incremental conductance (Inc. Cond.) MPPT, determines the maximum power by measuring the derivative of the PV voltage and current. The other method is based on reduced-rule compressed fuzzy logic control (RR-FLC), using which it is relatively easier to determine the maximum power because a single input variable is used to reduce computing loads. In this study, a 150-W PV panel system model was realized using these MPPT methods in MATLAB and the results compared. According to the simulation results, the proposed RR-FLC-based MPPT could increase the response rate and tracking accuracy by 4.66% under standard test conditions.

  15. Perturbation Training Can Reduce Community-Dwelling Older Adults’ Annual Fall Risk: A Randomized Controlled Trial

    Science.gov (United States)

    Bhatt, Tanvi; Yang, Feng; Wang, Edward

    2014-01-01

    Background. Previous studies indicated that a single session of repeated-slip exposure can reduce over 40% of laboratory-induced falls among older adults. The purpose of this study was to determine to what degree such perturbation training translated to the reduction of older adults’ annual falls risk in their everyday living. Methods. Two hundred and twelve community-dwelling older adults (≥65 years old) were randomly assigned to either the training group (N = 109), who then were exposed to 24 unannounced repeated slips, or the control group (N = 103), who merely experienced one slip during the same walking in the same protective laboratory environment. We recorded their falls in the preceding year (through self-reported history) and during the next 12 months (through falls diary and monitored with phone calls). Results. With this single session of repeated-slip exposure, training cut older adults’ annual risk of falls by 50% (from 34% to 15%, p fall during the same 12-month follow-up period (p falls. Conclusion. A single session of repeated-slip exposure could improve community-dwelling older adults’ resilience to postural disturbances and, hence, significantly reduce their annual risk of falls. PMID:24966227

  16. Perturbation training can reduce community-dwelling older adults' annual fall risk: a randomized controlled trial.

    Science.gov (United States)

    Pai, Yi-Chung; Bhatt, Tanvi; Yang, Feng; Wang, Edward

    2014-12-01

    Previous studies indicated that a single session of repeated-slip exposure can reduce over 40% of laboratory-induced falls among older adults. The purpose of this study was to determine to what degree such perturbation training translated to the reduction of older adults' annual falls risk in their everyday living. Two hundred and twelve community-dwelling older adults (≥65 years old) were randomly assigned to either the training group (N = 109), who then were exposed to 24 unannounced repeated slips, or the control group (N = 103), who merely experienced one slip during the same walking in the same protective laboratory environment. We recorded their falls in the preceding year (through self-reported history) and during the next 12 months (through falls diary and monitored with phone calls). With this single session of repeated-slip exposure, training cut older adults' annual risk of falls by 50% (from 34% to 15%, p fall during the same 12-month follow-up period (p falls. A single session of repeated-slip exposure could improve community-dwelling older adults' resilience to postural disturbances and, hence, significantly reduce their annual risk of falls. © The Author 2014. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  17. Effectiveness of Emission Controls to Reduce the Atmospheric Concentrations of Mercury.

    Science.gov (United States)

    Castro, Mark S; Sherwell, John

    2015-12-15

    Coal-fired power plants in the United States are required to reduce their emissions of mercury (Hg) into the atmosphere to lower the exposure of Hg to humans. The effectiveness of power-plant emission controls on the atmospheric concentrations of Hg in the United States is largely unknown because there are few long-term high-quality atmospheric Hg data sets. Here, we present the atmospheric concentrations of Hg and sulfur dioxide (SO2) measured from 2006 to 2015 at a relatively pristine location in western Maryland that is several (>50 km) kilometers downwind of power plants in Ohio, Pennsylvania, and West Virginia. Annual average atmospheric concentrations of gaseous oxidized mercury (GOM), SO2, fine particulate mercury (PBM2.5), and gaseous elemental mercury (GEM) declined by 75%, 75%, 43%, and 13%, respectively, and were strongly correlated with power-plant Hg emissions from the upwind states. These results provide compelling evidence that reductions in Hg emissions from power plants in the United States had their intended impact to reduce regional Hg pollution.

  18. Instabilities in power law gradient hardening materials

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Tvergaard, Viggo

    2005-01-01

    Tension and compression instabilities are investigated for specimens with dimensions in the micron range. A finite strain generalization of a higher order strain gradient plasticity theory is implemented in a finite element scheme capable of modeling power law hardening materials. Effects...... of gradient hardening are found to delay the onset of localization under plane strain tension, and significantly reduce strain gradients in the localized zone. For plane strain compression gradient hardening is found to increase the load-carrying capacity significantly....

  19. Evaluation of flurbiprofen in detrusor instability.

    OpenAIRE

    Cardozo, L D; Stanton, S L; Robinson, H; Hole, D

    1980-01-01

    Thirty women with detrusor instability (27 cases idiopathic, and three secondary to multiple sclerosis) completed a double-blind, cross-over trial of the prostaglandin synthetase inhibitor flurbiprofen and a placebo, results being evaluated by questionnaire and cystometry. Frequency, urgency, and urge incontinence were all significantly reduced with flurbiprofen (P less than 0.001, P less than 0.025, and P less than 0.025 respectively), as was the detrusor-pressure rise during bladder filling...

  20. Instabilities in mimetic matter perturbations

    Energy Technology Data Exchange (ETDEWEB)

    Firouzjahi, Hassan; Gorji, Mohammad Ali [School of Astronomy, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Mansoori, Seyed Ali Hosseini, E-mail: firouz@ipm.ir, E-mail: gorji@ipm.ir, E-mail: shosseini@shahroodut.ac.ir, E-mail: shossein@ipm.ir [Physics Department, Shahrood University of Technology, P.O. Box 3619995161 Shahrood (Iran, Islamic Republic of)

    2017-07-01

    We study cosmological perturbations in mimetic matter scenario with a general higher derivative function. We calculate the quadratic action and show that both the kinetic term and the gradient term have the wrong sings. We perform the analysis in both comoving and Newtonian gauges and confirm that the Hamiltonians and the associated instabilities are consistent with each other in both gauges. The existence of instabilities is independent of the specific form of higher derivative function which generates gradients for mimetic field perturbations. It is verified that the ghost instability in mimetic perturbations is not associated with the higher derivative instabilities such as the Ostrogradsky ghost.

  1. Controle de plantas daninhas em soja com doses reduzidas de herbicidas Soybean weed control with reduced rates of herbicides

    Directory of Open Access Journals (Sweden)

    Nilson G. Fleck

    1995-01-01

    Full Text Available doses reduzidas dos herbicidas haloxyfop-methyl e sethoxydim para controlar papuã [Brachiaria plantaginea (Link Hitchc.] na cultura da soja [Glycine max (L. Merrill. Haloxyfop-methyl foi testado nas doses de 120, 90, 60 e 30+30 g/ha; já sethoxydim o foi nas doses de 220, 165, 110 e 55+55 g/ha. A pulverização dos herbicidas ocorreu 15 dias após a semeadura da soja; nesta ocasião, a maioria das plantas de papuã encontravam-se no estádio de três a quatro folhas. Os tratamentos herbicidas com doses reduzidas em aplicações seqüenciais, tiveram a segunda pulverização realizada 11 dias após a primeira aplicação. Foi obtido controle ao redor de 95% para todos os tratamentos, com pequenas variações não significativas. O rendimento de grãos de soja foi equivalente entre a testemunha capinada e os tratamentos haloxyfop-methyl a 90 e 60 g/ha, sethoxydim a 220, 110 e 55+55 g/ha. Os demais tratamentos foram semelhantes entre si, superando a testemunha infestada, a qual apresentou o menor rendimento de grãos. Os resultados evidenciam a viabilidade da utilização de doses reduzidas, as quais podem alcançar patamares de produtividade tão elevados quanto aqueles obtidos com doses plenas.During the 1993/94 growing season, it was carried out a field experiment at the Agronomic Experimental Station of Federal University of Rio Grande do Sul, in Eldorado do Sul, RS, Brazil, in order to evaluate the possibility of using reduced rates of the herbicides haloxyfop-methyl and sethoxydim for Alexandergrass [Brachiaria plafitaginea (Link Hitchc.] control in soybeans. Haloxyfop-methyl was tested at 120, 90, 60, and 30+30 g/ha, where as sethoxydim was at rates, of 220, 165, 110, and 55+55 g/ha. Herbicide spraying occurred 15 days after soybean sowing; at this time Alexandergrass plants ranged from one leaf to one tiller. Herbicide treatments using reduced rates in sequential applications had the second spraying accomplished 11 days after the first one

  2. Reducing methods of patients exposed dose using auto exposure control system in digital radiography

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Seong Gyu [Dept. of Diagnostic Radiology, Dong A University Medical Center, Busan (Korea, Republic of)

    2013-06-15

    This study was carried out to reduce patient dose through focus-detector distance, kilovoltage, and a combination of copper filters. In the C, L-spine lateral, Skull AP views were obtained by making changes of 60-100 kV in tube voltage and of 100-200 cm in focus-detector distance and by adding a copper filter when using an auto exposure control device in the digital radiography equipment. The incident dose showed 90 kV, 0.3 mmCu in C-spine lateral with 0.06 mGy under the condition of 200 cm; 100 kV, 0.3 mmCu with 0.40 mGy under the condition of 200 cm and 90 kV 0.3 mmCu in Skull AP with the lowest value of 0.24 mGy under the condition of 140 cm. It was observed that entrance surface dose decreased the most when was increased by 150 cm, 70 kV (C-spine lateral), 81 kV (L-spine lateral). It was also found out that as the between the focus-detector increased in the expansion of the video decreased but the difference was not significant when the distance was 180 cm or more. Skull AP showed the most reduction in the entrance surface dose when the tube voltage was changed by 80 kV, 0.1 mmCu, and 120 cm. Therefore, when using the automatic exposure control device, it is recommended to use the highest tube voltage if possible and to increase focus-detector distance at least by 150-200 cm in wall and 120-140 cm in table in consideration of the radiotechnologist's physical conditions, and to combine 0.1-0.3 mmCu and higher filters. It is thus expected to reduce patient dose by avoiding distortion of images and reducing the entrance surface dose.

  3. 3D Relativistic Magnetohydrodynamic Simulations of Current-Driven Instability. 1; Instability of a Static Column

    Science.gov (United States)

    Mizuno, Yosuke; Lyubarsky, Yuri; ishikawa, Ken-Ichi; Hardee, Philip E.

    2010-01-01

    We have investigated the development of current-driven (CD) kink instability through three-dimensional relativistic MHD simulations. A static force-free equilibrium helical magnetic configuration is considered in order to study the influence of the initial configuration on the linear and nonlinear evolution of the instability. We found that the initial configuration is strongly distorted but not disrupted by the kink instability. The instability develops as predicted by linear theory. In the non-linear regime the kink amplitude continues to increase up to the terminal simulation time, albeit at different rates, for all but one simulation. The growth rate and nonlinear evolution of the CD kink instability depends moderately on the density profile and strongly on the magnetic pitch profile. The growth rate of the kink mode is reduced in the linear regime by an increase in the magnetic pitch with radius and the non-linear regime is reached at a later time than for constant helical pitch. On the other hand, the growth rate of the kink mode is increased in the linear regime by a decrease in the magnetic pitch with radius and reaches the non-linear regime sooner than the case with constant magnetic pitch. Kink amplitude growth in the non-linear regime for decreasing magnetic pitch leads to a slender helically twisted column wrapped by magnetic field. On the other hand, kink amplitude growth in the non-linear regime nearly ceases for increasing magnetic pitch.

  4. Mindfulness practice reduces cortisol blunting during chemotherapy: A randomized controlled study of colorectal cancer patients.

    Science.gov (United States)

    Black, David S; Peng, Cheng; Sleight, Alix G; Nguyen, Nathalie; Lenz, Heinz-Josef; Figueiredo, Jane C

    2017-08-15

    The objective of this randomized clinical experiment was to test the influence of a mindfulness meditation practice, when delivered during 1 session of active chemotherapy administration, on the acute salivary cortisol response as a marker of neuroendocrine system activity in cancer patients. A mindfulness, attention-control, or resting exposure was assigned to 57 English- or Spanish-speaking colorectal cancer patients at 1 county oncology clinic and 1 university oncology clinic at the start of chemotherapy. Saliva samples were collected at the start of chemotherapy and at subsequent 20-minute intervals during the first 60 minutes of chemotherapy (4 samples in all). Self-reporting on biobehavioral assessments after chemotherapy included distress, fatigue, and mindfulness. An area-under-the-curve analysis (AUC) showed a relative increase in cortisol reactivity in the mindfulness group after adjustments for biological and clinical measures (β = 123.21; P = .03). More than twice as many patients in the mindfulness group versus the controls displayed a cortisol rise from the baseline to 20 minutes (69% vs 34%; P = .02). AUC values were uncorrelated with biobehavioral measure scores, although mindfulness scores were inversely correlated with fatigue (r = -0.46; P mindfulness practice during chemotherapy can reduce the blunting of neuroendocrine profiles typically observed in cancer patients. Implications include support for the use of mindfulness practice in integrative oncology. Cancer 2017;123:3088-96. © 2017 American Cancer Society. © 2017 American Cancer Society.

  5. Reducing Postpartum Weight Retention and Improving Breastfeeding Outcomes in Overweight Women: A Pilot Randomised Controlled Trial

    Directory of Open Access Journals (Sweden)

    Julia Martin

    2015-02-01

    Full Text Available Overweight and obesity is prevalent among women of reproductive age (42% BMI > 25 kg/m2 and parity is associated with risk of weight gain. Weight gain greater than that recommended by the Institute of Medicine (IOM is also associated with lower rates of breastfeeding initiation and duration in women. The aim of this pilot randomised controlled trial is to examine the feasibility of recruiting and maintaining a cohort of pregnant women with the view of reducing postpartum weight retention and improving breastfeeding outcomes. Women (BMI of 25–35 kg/m2 (n = 36 were recruited from the John Hunter Hospital antenatal clinic in New South Wales, Australia. Participants were stratified by BMI and randomised to one of three groups with follow-up to six months postpartum. Women received a dietary intervention with or without breastfeeding support from a lactation consultant, or were assigned to a wait-list control group where the dietary intervention was issued at three months postpartum. Feasibility and acceptability was assessed by participation rates and questionnaire. Analysis of variance and covariance was conducted to determine any differences between groups. Sixty-nine per cent of the participants were still enrolled at six months postpartum. This pilot demonstrated some difficulties in recruiting women from antenatal clinics and retaining them in the trial. Although underpowered; the results on weight; biomarkers and breastfeeding outcomes indicated improved metabolic health.

  6. 3D analyses of cavitation instabilities accounting for plastic anisotropy

    DEFF Research Database (Denmark)

    Legarth, Brian Nyvang; Tvergaard, Viggo

    2010-01-01

    Full three dimensional cell model analyses are carried out for a solid containing a single small void, in order to determine the critical stress levels for the occurrence of cavitation instabilities. The material models applied are elastic‐viscoplastic, with a small rate‐hardening exponent...... that the quasi‐static solution is well approximated. A special procedure is used to strongly reduce the loading rate a little before the instability occurs. It is found that plastic anisotropy has a significant effect on the level of the critical stress for cavitation instabilities....

  7. Circuit effects on pierce instabilities, and double-layer formation

    International Nuclear Information System (INIS)

    Raadu, M.A.; Silevitch, M.B.

    1982-11-01

    The role of the Pierce instability in the formation of double layers is considered and compared with that of the Buneman instability. Pierce instabilities have been identified in a double-layer experiment, where they lead to ion trapping. Here the effects of external circuit elements are considered. In the case of immobile ions the onset criteria are unaffected, but in the unstable range the growth rate is reduced by the external impedance. Required experimental values of the circuit elements are estimated. The possible relevance to computer simulations is noted. (Authors)

  8. Participatory workplace interventions can reduce sedentary time for office workers--a randomised controlled trial.

    Science.gov (United States)

    Parry, Sharon; Straker, Leon; Gilson, Nicholas D; Smith, Anne J

    2013-01-01

    Occupational sedentary behaviour is an important contributor to overall sedentary risk. There is limited evidence for effective workplace interventions to reduce occupational sedentary time and increase light activity during work hours. The purpose of the study was to determine if participatory workplace interventions could reduce total sedentary time, sustained sedentary time (bouts >30 minutes), increase the frequency of breaks in sedentary time and promote light intensity activity and moderate/vigorous activity (MVPA) during work hours. A randomised controlled trial (ANZCTR NUMBER: ACTN12612000743864) was conducted using clerical, call centre and data processing workers (n = 62, aged 25-59 years) in 3 large government organisations in Perth, Australia. Three groups developed interventions with a participatory approach: 'Active office' (n = 19), 'Active Workstation' and promotion of incidental office activity; 'Traditional physical activity' (n = 14), pedometer challenge to increase activity between productive work time and 'Office ergonomics' (n = 29), computer workstation design and breaking up computer tasks. Accelerometer (ActiGraph GT3X, 7 days) determined sedentary time, sustained sedentary time, breaks in sedentary time, light intensity activity and MVPA on work days and during work hours were measured before and following a 12 week intervention period. For all participants there was a significant reduction in sedentary time on work days (-1.6%, p = 0.006) and during work hours (-1.7%, p = 0.014) and a significant increase in number of breaks/sedentary hour on work days (0.64, p = 0.005) and during work hours (0.72, p = 0.015); there was a concurrent significant increase in light activity during work hours (1.5%, p = 0.012) and MVPA on work days (0.6%, p = 0.012). This study explored novel ways to modify work practices to reduce occupational sedentary behaviour. Participatory workplace interventions can reduce

  9. Effectiveness of comprehensive tobacco control programmes in reducing teenage smoking in the USA.

    Science.gov (United States)

    Wakefield, M; Chaloupka, F

    2000-06-01

    To describe the extent to which comprehensive statewide tobacco control programmes in the USA have made progress toward reducing teenage smoking. Literature search of Medline for reviews of effectiveness of programme and policy elements, plus journal articles and personal request for copies of publicly released reports and working papers from evaluation staff in each of the state programmes of California, Massachusetts, Arizona, Oregon, and Florida. All studies, reports, and commentaries that provided information on aspects of programme implementation and evaluation. Statewide comprehensive programmes show high levels of advertising recall and generally positive improvement in smoking related beliefs and attitudes among teenagers. More fully funded programmes lead to increased mass media campaign advertising and community initiatives; a greater capacity to implement school based smoking prevention programmes; and an increase in the passage of local ordinances that create smoke free indoor environments and reduce cigarette sales to youth. The combination of programme activity and increased tobacco tax reduce cigarette consumption more than expected as a result of price increases alone, and these effects seem to apply to adolescents as well as adults. Programmes are associated with a decline in adult smoking prevalence, with these effects observed to date in California, Massachusetts, and Oregon. Arizona and Florida have yet to examine change in adult prevalence associated with programme exposure. California and Massachusetts have demonstrated relative beneficial effects in teenage smoking prevalence, and Florida has reported promising indications of reduced prevalence. Arizona has yet to report follow up data, and Oregon has found no change in teenage smoking, but has only two years of follow up available. One of the most critical factors in programme success is the extent of programme funding, and consequent level of programme implementation, and the degree to

  10. Participatory workplace interventions can reduce sedentary time for office workers--a randomised controlled trial.

    Directory of Open Access Journals (Sweden)

    Sharon Parry

    Full Text Available BACKGROUND: Occupational sedentary behaviour is an important contributor to overall sedentary risk. There is limited evidence for effective workplace interventions to reduce occupational sedentary time and increase light activity during work hours. The purpose of the study was to determine if participatory workplace interventions could reduce total sedentary time, sustained sedentary time (bouts >30 minutes, increase the frequency of breaks in sedentary time and promote light intensity activity and moderate/vigorous activity (MVPA during work hours. METHODS: A randomised controlled trial (ANZCTR NUMBER: ACTN12612000743864 was conducted using clerical, call centre and data processing workers (n = 62, aged 25-59 years in 3 large government organisations in Perth, Australia. Three groups developed interventions with a participatory approach: 'Active office' (n = 19, 'Active Workstation' and promotion of incidental office activity; 'Traditional physical activity' (n = 14, pedometer challenge to increase activity between productive work time and 'Office ergonomics' (n = 29, computer workstation design and breaking up computer tasks. Accelerometer (ActiGraph GT3X, 7 days determined sedentary time, sustained sedentary time, breaks in sedentary time, light intensity activity and MVPA on work days and during work hours were measured before and following a 12 week intervention period. RESULTS: For all participants there was a significant reduction in sedentary time on work days (-1.6%, p = 0.006 and during work hours (-1.7%, p = 0.014 and a significant increase in number of breaks/sedentary hour on work days (0.64, p = 0.005 and during work hours (0.72, p = 0.015; there was a concurrent significant increase in light activity during work hours (1.5%, p = 0.012 and MVPA on work days (0.6%, p = 0.012. CONCLUSIONS: This study explored novel ways to modify work practices to reduce occupational sedentary behaviour

  11. Instability characteristics of fluidelastic instability of tube rows in crossflow

    International Nuclear Information System (INIS)

    Chen, S.S.; Jendrzejczyk, J.A.

    1986-04-01

    An experimental study is reported to investigate the jump phenomenon in critical flow velocities for tube rows with different pitch-to-diameter ratios and the excited and intrinsic instabilities for a tube row with a pitch-to-diameter ratio of 1.75. The experimental data provide additional insights into the instability phenomena of tube arrays in crossflow. 9 refs., 10 figs

  12. Educational outreach to general practitioners reduces children's asthma symptoms: a cluster randomised controlled trial

    Directory of Open Access Journals (Sweden)

    Sladden Michael

    2007-09-01

    Full Text Available Abstract Background Childhood asthma is common in Cape Town, a province of South Africa, but is underdiagnosed by general practitioners. Medications are often prescribed inappropriately, and care is episodic. The objective of this study is to assess the impact of educational outreach to general practitioners on asthma symptoms of children in their practice. Methods This is a cluster randomised trial with general practices as the unit of intervention, randomisation, and analysis. The setting is Mitchells Plain (population 300,000, a dormitory town near Cape Town. Solo general practitioners, without nurse support, operate from storefront practices. Caregiver-reported symptom data were collected for 318 eligible children (2 to 17 years with moderate to severe asthma, who were attending general practitioners in Mitchells Plain. One year post-intervention follow-up data were collected for 271 (85% of these children in all 43 practices. Practices randomised to intervention (21 received two 30-minute educational outreach visits by a trained pharmacist who left materials describing key interventions to improve asthma care. Intervention and control practices received the national childhood asthma guideline. Asthma severity was measured in a parent-completed survey administered through schools using a symptom frequency and severity scale. We compared intervention and control group children on the change in score from pre-to one-year post-intervention. Results Symptom scores declined an additional 0.84 points in the intervention vs. control group (on a nine-point scale. p = 0.03. For every 12 children with asthma exposed to a doctor allocated to the intervention, one extra child will have substantially reduced symptoms. Conclusion Educational outreach was accepted by general practitioners and was effective. It could be applied to other health care quality problems in this setting.

  13. Mechanisms of cadmium induced genomic instability

    Energy Technology Data Exchange (ETDEWEB)

    Filipic, Metka, E-mail: metka.filipic@nib.si [National Institute of Biology, Department for Genetic Toxicology and Cancer Biology, Ljubljana (Slovenia)

    2012-05-01

    Cadmium is an ubiquitous environmental contaminant that represents hazard to humans and wildlife. It is found in the air, soil and water and, due to its extremely long half-life, accumulates in plants and animals. The main source of cadmium exposure for non-smoking human population is food. Cadmium is primarily toxic to the kidney, but has been also classified as carcinogenic to humans by several regulatory agencies. Current evidence suggests that exposure to cadmium induces genomic instability through complex and multifactorial mechanisms. Cadmium dose not induce direct DNA damage, however it induces increase in reactive oxygen species (ROS) formation, which in turn induce DNA damage and can also interfere with cell signalling. More important seems to be cadmium interaction with DNA repair mechanisms, cell cycle checkpoints and apoptosis as well as with epigenetic mechanisms of gene expression control. Cadmium mediated inhibition of DNA repair mechanisms and apoptosis leads to accumulation of cells with unrepaired DNA damage, which in turn increases the mutation rate and thus genomic instability. This increases the probability of developing not only cancer but also other diseases associated with genomic instability. In the in vitro experiments cadmium induced effects leading to genomic instability have been observed at low concentrations that were comparable to those observed in target organs and tissues of humans that were non-occupationally exposed to cadmium. Therefore, further studies aiming to clarify the relevance of these observations for human health risks due to cadmium exposure are needed.

  14. Mechanisms of cadmium induced genomic instability

    International Nuclear Information System (INIS)

    Filipič, Metka

    2012-01-01

    Cadmium is an ubiquitous environmental contaminant that represents hazard to humans and wildlife. It is found in the air, soil and water and, due to its extremely long half-life, accumulates in plants and animals. The main source of cadmium exposure for non-smoking human population is food. Cadmium is primarily toxic to the kidney, but has been also classified as carcinogenic to humans by several regulatory agencies. Current evidence suggests that exposure to cadmium induces genomic instability through complex and multifactorial mechanisms. Cadmium dose not induce direct DNA damage, however it induces increase in reactive oxygen species (ROS) formation, which in turn induce DNA damage and can also interfere with cell signalling. More important seems to be cadmium interaction with DNA repair mechanisms, cell cycle checkpoints and apoptosis as well as with epigenetic mechanisms of gene expression control. Cadmium mediated inhibition of DNA repair mechanisms and apoptosis leads to accumulation of cells with unrepaired DNA damage, which in turn increases the mutation rate and thus genomic instability. This increases the probability of developing not only cancer but also other diseases associated with genomic instability. In the in vitro experiments cadmium induced effects leading to genomic instability have been observed at low concentrations that were comparable to those observed in target organs and tissues of humans that were non-occupationally exposed to cadmium. Therefore, further studies aiming to clarify the relevance of these observations for human health risks due to cadmium exposure are needed.

  15. Kinetic instabilities in relativistic plasmas: the Harris instability revisited

    International Nuclear Information System (INIS)

    Tautz, R.C.

    2008-01-01

    Plasma instabilities that generate aperiodic fluctuations are of outstanding importance in the astrophysical context. Two prominent examples are the electromagnetic Weibel instability and the electrostatic Harris instability, which operate in initially non-magnetized and magnetized plasmas, respectively. In this talk, the original formulation of the Harris instability will be reviewed and generalizations will be presented such as the inclusion of (1) relativistic effects, (2) ion effects, and (3) mode coupling. It will be shown that, with these modifications, a powerful method has been developed for the determination of both the existence and the growth rate of low-frequency instabilities. Applications can be found in astrophysical jets, where the rest frame can be used and so no parallel motion is present. At the end of the talk, how the particle composition of gamma-ray burst jets can be predicted using the Harris technique. (author)

  16. Chinese phytotherapy to reduce stress, anxiety and improve quality of life: randomized controlled trial.

    Science.gov (United States)

    Kurebayashi, Leonice Fumiko Sato; Turrini, Ruth Natalia Teresa; Kuba, Gisele; Shimizu, Miki Hoshi Minamizawa; Takiguch, Raymond Sehiji

    2016-01-01

    To evaluate the effect of Chinese phytotherapyto reduce stress levels, anxiety and improve quality of life. double-blind randomized controlled trial with 89 volunteers divided into three groups: control (no intervention), Placebo and Phytotherapy. The study was conducted in 2015 with healthy adults treated at the Integrated and Eastern Therapy Institute,in Sao Paulo, Brazil. Participants were evaluated at baseline and after three weeks with the Stress Symptoms List (SSL), Anxiety Inventory-Trait and State and SF12v2 for quality of life. Intervention groups received a placebo or Gan May Zao formula (GMDZ)flaskwith 50 ml. According to ANOVA, there were significant differences (p = 0.025) after treatment of stress (SSL2). And the difference was between control and Phytotherapy groups, according to the Tukey post hoc (p = 0.022). There were no differences in the levels of state-anxiety and physical and mental domains in the SF12v2. The GMDZ formula reduced stress levels, but more studies are needed with greater sample, with reassessment of dosage and a longer period of treatment to confirm and extend the results. Brazilian Registry of Clinical Trials: RBR-28s4hz. Avaliar o efeito da fitoterapia chinesa na redução de níveis de estresse, ansiedade e melhoria de qualidade de vida. Ensaio clínico randomizado duplo-cego, com 89 voluntários divididos em três grupos: Controle (sem intervenção), Placebo e Fitoterapia. Foi realizado em 2015, com adultos saudáveis atendidos no Instituto de Terapia Integrada e Oriental, São Paulo. Foram avaliados no baseline e, após 3 semanas,pela Lista de Sintomas de Stress (LSS), Inventário de Ansiedade-Traço e Estado e o SF12v2 de qualidade de vida. Os grupos de intervenção receberam um frasco de 50 ml de placebo ou da fórmula Gan Mai Da Zao (GMDZ). Segundo ANOVA, houve diferença (p=0,025) no pós-tratamento de estresse (LSS2). E a diferença foi entre os grupos Controle e Fitoterapia, de acordo com o post hocde Tukey (p=0

  17. Mechanical and chemical spinodal instabilities in finite quantum systems

    International Nuclear Information System (INIS)

    Colonna, M.; Chomaz, Ph.; Ayik, S.

    2001-01-01

    Self consistent quantum approaches are used to study the instabilities of finite nuclear systems. The frequencies of multipole density fluctuations are determined as a function of dilution and temperature, for several isotopes. The spinodal region of the phase diagrams is determined and it appears reduced by finite size effects. The role of surface and volume instabilities is discussed. Important chemical effects are associated with mechanical disruption and may lead to isospin fractionation. (authors)

  18. The Efficacy of Prescribed Casual Videogame Play in Reducing Symptoms of Anxiety: A Randomized Controlled Study.

    Science.gov (United States)

    Fish, Matthew T; Russoniello, Carmen V; O'Brien, Kevin

    2014-10-01

    Anxiety is a natural reaction to stress, but when excessive, it can develop into a debilitating disorder. Traditional treatments such as pharmaceuticals and psychotherapy have demonstrated efficacy in alleviating anxiety symptoms but are often costly and stigmatizing. This study tested whether a regimen of prescribed casual videogame (CVG) play could reduce individuals' anxiety symptom severity in a depressed population. CVGs are defined as fun, easy to play, spontaneous, and extremely popular. Data were taken from a larger study on depression and CVGs. Participants were screened for depression using a score of ≥5 (mild depression) on the Patient Health Questionnaire-9. After completing pre-intervention questionnaires, participants were randomized into the experimental (n=30) or control (n=29) group. Participants in the experimental group were prescribed a CVG of their choice to play three times per week, for 30 minutes, over a 1-month period. The State Trait Anxiety Inventory (STAI) was used to test the hypothesis. Repeated-measures analysis of variance revealed significant interaction of group by time for state and trait anxiety measures, supporting the hypothesis that anxiety severity would be different by group post-intervention. When state and trait anxiety measures were compared using within-subjects contrasts and between-group analyses, significant decreases in anxiety symptom severity were demonstrated. A prescribed regimen of CVG play significantly reduced state and trait anxiety symptom severity as measured by the STAI. Clinicians should consider using these easy-to-use and low-cost CVGs to address symptoms associated with state and trait anxiety.

  19. Energy cost of running instability evaluated with wearable trunk accelerometry.

    Science.gov (United States)

    Schütte, Kurt H; Sackey, Saint; Venter, Rachel; Vanwanseele, Benedicte

    2018-02-01

    Maintaining stability under dynamic conditions is an inherent challenge to bipedal running. This challenge may impose an energetic cost (Ec) thus hampering endurance running performance, yet the underlying mechanisms are not clear. Wireless triaxial trunk accelerometry is a simple tool that could be used to unobtrusively evaluate these mechanisms. Here, we test a cost of instability hypothesis by examining the contribution of trunk accelerometry-based measures (triaxial root mean square, step and stride regularity, and sample entropy) to interindividual variance in Ec (J/m) during treadmill running. Accelerometry and indirect calorimetry data were collected concurrently from 30 recreational runners (16 men; 14 women) running at their highest steady-state running speed (80.65 ± 5.99% V̇o 2max ). After reducing dimensionality with factor analysis, the effect of dynamic stability features on Ec was evaluated using hierarchical multiple regression analysis. Three accelerometry-based measures could explain an additional 10.4% of interindividual variance in Ec after controlling for body mass, attributed to anteroposterior stride regularity (5.2%), anteroposterior root mean square ratio (3.2%), and mediolateral sample entropy (2.0%). Our results lend support to a cost of instability hypothesis, with trunk acceleration waveform signals that are 1) more consistent between strides anteroposterioly, 2) larger in amplitude variability anteroposterioly, and 3) more complex mediolaterally and are energetically advantageous to endurance running performance. This study shows that wearable trunk accelerometry is a useful tool for understanding the Ec of running and that running stability is important for economy in recreational runners. NEW & NOTEWORTHY This study evaluates and more directly lends support to a cost of instability hypothesis between runners. Moreover, this hypothesis was tested using a minimalist setup including a single triaxial trunk mounted accelerometer

  20. Numerical study of the effect of inlet geometry on combustion instabilities in a lean premixed swirl combustor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chang Eon [Dept. of Mechanical Engineering, Inha University, Incheon (Korea, Republic of); Park, Seul Hyun [Dept. of Mechanical Systems Engineering, Chosun University, Gwangju (Korea, Republic of); Hwang, Cheol Hong [Dept. of Fire and Disaster Prevention, Daejeon University, Daejeon (Korea, Republic of)

    2016-11-15

    The effects of flow structure and flame dynamics on combustion instabilities in a lean premixed swirl combustor were numerically investigated using Large eddy simulation (LES) by varying the inlet geometry of combustor. The dynamic ksgs-equation and G-equation flamelet models were respectively employed as the LES subgrid models of turbulence and combustion. The divergent half angle (α) in the combustor inlet was varied systematically from 30° to 90° to quantify the effect of inlet geometry on the combustion instabilities. This variation caused considerable deformation in recirculation zones in terms of their size and location, leading to significant changes in flame dynamics. Analysis of unsteady pressure distributions in the combustor showed that the largest damping caused by combustion instabilities takes place at α = 45°, and the amplitude of acoustic pressure oscillation is largest at α = 30°. Examination of local Rayleigh parameters indicated that controlling flame-vortex interactions by modifying inlet geometry can change the local characteristics of combustion instabilities in terms of their amplification and suppression, and thus serve as a useful approach to reduce the instabilities in a lean premixed swirl combustor. These phenomena were studied in detail through unsteady analysis associated with flow and flame dynamics.

  1. Numerical study of the effect of inlet geometry on combustion instabilities in a lean premixed swirl combustor

    International Nuclear Information System (INIS)

    Lee, Chang Eon; Park, Seul Hyun; Hwang, Cheol Hong

    2016-01-01

    The effects of flow structure and flame dynamics on combustion instabilities in a lean premixed swirl combustor were numerically investigated using Large eddy simulation (LES) by varying the inlet geometry of combustor. The dynamic ksgs-equation and G-equation flamelet models were respectively employed as the LES subgrid models of turbulence and combustion. The divergent half angle (α) in the combustor inlet was varied systematically from 30° to 90° to quantify the effect of inlet geometry on the combustion instabilities. This variation caused considerable deformation in recirculation zones in terms of their size and location, leading to significant changes in flame dynamics. Analysis of unsteady pressure distributions in the combustor showed that the largest damping caused by combustion instabilities takes place at α = 45°, and the amplitude of acoustic pressure oscillation is largest at α = 30°. Examination of local Rayleigh parameters indicated that controlling flame-vortex interactions by modifying inlet geometry can change the local characteristics of combustion instabilities in terms of their amplification and suppression, and thus serve as a useful approach to reduce the instabilities in a lean premixed swirl combustor. These phenomena were studied in detail through unsteady analysis associated with flow and flame dynamics

  2. Instabilities in the aether

    International Nuclear Information System (INIS)

    Carroll, Sean M.; Dulaney, Timothy R.; Gresham, Moira I.; Tam, Heywood

    2009-01-01

    We investigate the stability of theories in which Lorentz invariance is spontaneously broken by fixed-norm vector 'aether' fields. Models with generic kinetic terms are plagued either by ghosts or by tachyons, and are therefore physically unacceptable. There are precisely three kinetic terms that are not manifestly unstable: a sigma model (∂ μ A ν ) 2 , the Maxwell Lagrangian F μν F μν , and a scalar Lagrangian (∂ μ A μ ) 2 . The timelike sigma-model case is well defined and stable when the vector norm is fixed by a constraint; however, when it is determined by minimizing a potential there is necessarily a tachyonic ghost, and therefore an instability. In the Maxwell and scalar cases, the Hamiltonian is unbounded below, but at the level of perturbation theory there are fewer degrees of freedom and the models are stable. However, in these two theories there are obstacles to smooth evolution for certain choices of initial data.

  3. Posterolateral elbow joint instability

    DEFF Research Database (Denmark)

    Olsen, Bo Sanderhoff; Søjbjerg, Jens Ole; Nielsen, K K

    1998-01-01

    Thirty-five osteoligamentous elbows were included in a study on the kinematics of posterolateral elbow joint instability during the pivot shift test (PST) before and after separate ligament cuttings in the lateral collateral ligament complex (LCLC). Division of the annular ligament or the lateral...... ulnar collateral ligament caused no laxity during the PST. Division of the lateral collateral ligament caused maximal laxity of 4 degrees and 23 degrees during forced PST in valgus and external rotation (supination), respectively. Cutting of the LCLC at the ulnar or the humeral insertion was necessary...... for any PST stressed elbow joint laxity to occur. Total division of the LCLC induced a maximal laxity of 7.9 degrees and 37 degrees during forced PST in valgus and external rotation (supination), respectively. This study suggests the lateral collateral ligament to be the primary soft tissue constraint...

  4. Instabilities in electromagnetic quasilevitation.

    Science.gov (United States)

    Spragg, Kirk; Letout, Sebastien; Ernst, R; Sneyd, Alfred; Fautrelle, Yves

    2014-05-01

    We investigate free-surface instabilities occurring in various industrial processes involving liquid metal. Of particular interest is the behavior of the free surface of a pool of liquid metal when it is submitted to an alternating magnetic field. Experimentally, we study the effect of a vertical alternating medium-frequency magnetic field on an initially circular pool. We observe various types of behavior according to magnetic field amplitude, e.g., axisymmetric deformations, azimuthal mode structures, slow radial oscillation of the pool perimeter, and random rotation of the pool around its center. Drop rotation could be attributed to nonsymmetric shape deformations. The effect of oxidation leads to drastic changes in pool behavior. The experimental results are then compared to a linear stability analysis of the free surface of a circular liquid drop.

  5. From instabilities to multifragmentation

    International Nuclear Information System (INIS)

    Chomaz, P.; Jacquot, B.; Colonna, M.; Guarnera, A.

    1994-01-01

    The main purpose of this article is to show that, in many physical situations, the spinodal decomposition of unstable systems can be correctly described by stochastic mean-field approaches. Such theories predict that the occurrence of spinodal instability leading the multifragmentation of an expended nuclear system, can be signed through the observation of time scales for the fragment formation of the order of 100 fm/c and of typical fragment size around A=20. We will finally discuss the fact that these fragments are formed at finite temperature and so can subsequently decay in flight. Finally, we will give some hints about possible experimental signals of such first order phase transitions. (authors). 12 refs., 5 figs

  6. From instabilities to multifragmentation

    Energy Technology Data Exchange (ETDEWEB)

    Chomaz, P.; Jacquot, B. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France); Colonna, M.; Guarnera, A. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France)]|[Istituto Nazionale di Fisica Nucleare, Bologna (Italy)

    1994-12-31

    The main purpose of this article is to show that, in many physical situations, the spinodal decomposition of unstable systems can be correctly described by stochastic mean-field approaches. Such theories predict that the occurrence of spinodal instability leading the multifragmentation of an expended nuclear system, can be signed through the observation of time scales for the fragment formation of the order of 100 fm/c and of typical fragment size around A=20. We will finally discuss the fact that these fragments are formed at finite temperature and so can subsequently decay in flight. Finally, we will give some hints about possible experimental signals of such first order phase transitions. (authors). 12 refs., 5 figs.

  7. Saturation of equatorial inertial instability

    NARCIS (Netherlands)

    Kloosterziel, R.C.; Orlandi, P.; Carnevale, G.F.

    2015-01-01

    Inertial instability in parallel shear flows and circular vortices in a uniformly rotating system ( $f$f-plane) redistributes absolute linear momentum or absolute angular momentum in such a way as to neutralize the instability. In previous studies we showed that, in the absence of other

  8. Population-based biomedical sexually transmitted infection control interventions for reducing HIV infection.

    Science.gov (United States)

    Ng, Brian E; Butler, Lisa M; Horvath, Tara; Rutherford, George W

    2011-03-16

    to a 42% reduction (95% CI 21.0% - 58.0%) in HIV incidence in the intervention group. Another study, conducted in rural southwestern Uganda, showed that the aRR of behavioural intervention and STI management compared to control on HIV incidence was 1.00 (95% CI 0.63 - 1.58). In the third STI management trial, in eastern Zimbabwe, there was no effect of the intervention on HIV incidence (aRR = 1.3, 95% CI 0.92 - 1.8). These are consistent with data from the mass treatment trial showing no intervention effect. Overall, pooling the data of the four studies showed no significant effect of any intervention (rate ratio [RR] = 0.97, 95% CI 0.78 - 1.2).Combining the mass treatment trial and one of the STI management trials, we find that there is a significant 12.0% reduction in the prevalence of syphilis for those receiving a biomedical STI intervention (RR 0.88, 95% CI 0.80 - 0.96). For gonorrhoea, we find a statistically significant 51.0% reduction in its prevalence in those receiving any of these interventions (RR 0.49, 95% CI 0.31 - 0.77). Finally, for chlamydia, we found no significant difference between any biomedical intervention and control (RR 1.03, 95% CI 0.77 - 1.4). We failed to confirm the hypothesis that STI control is an effective HIV prevention strategy. Improved STI treatment services were shown in one study to reduce HIV incidence in an environment characterised by an emerging HIV epidemic (low and slowly rising prevalence), where STI treatment services were poor and where STIs were highly prevalent; Incidence was not reduced in two other settings. There is no evidence for substantial benefit from a presumptive treatment intervention for all community members. There are, however, other compelling reasons why STI treatment services should be strengthened, and the available evidence suggests that when an intervention is accepted it can substantially improve quality of services provided.

  9. Semiconductor Lasers Stability, Instability and Chaos

    CERN Document Server

    Ohtsubo, Junji

    2013-01-01

    This third edition of “Semiconductor Lasers, Stability, Instability and Chaos” was significantly extended.  In the previous edition, the dynamics and characteristics of chaos in semiconductor lasers after the introduction of the fundamental theory of laser chaos and chaotic dynamics induced by self-optical feedback and optical injection was discussed. Semiconductor lasers with new device structures, such as vertical-cavity surface-emitting lasers and broad-area semiconductor lasers, are interesting devices from the viewpoint of chaotic dynamics since they essentially involve chaotic dynamics even in their free-running oscillations. These topics are also treated with respect to the new developments in the current edition. Also the control of such instabilities and chaos control are critical issues for applications. Another interesting and important issue of semiconductor laser chaos in this third edition is chaos synchronization between two lasers and the application to optical secure communication. One o...

  10. Disease Control After Reduced Volume Conformal and Intensity Modulated Radiation Therapy for Childhood Craniopharyngioma

    Energy Technology Data Exchange (ETDEWEB)

    Merchant, Thomas E., E-mail: thomas.merchant@stjude.org [St Jude Children' s Research Hospital, Radiological Sciences, Memphis, Tennessee (United States); Kun, Larry E.; Hua, Chia-Ho [St Jude Children' s Research Hospital, Radiological Sciences, Memphis, Tennessee (United States); Wu, Shengjie; Xiong, Xiaoping [St Jude Children' s Research Hospital, Biostatistics, Memphis, Tennessee (United States); Sanford, Robert A.; Boop, Frederick A. [Semmes Murphey Neurologic and Spine Institute, Neurosurgery, Memphis, Tennessee (United States)

    2013-03-15

    Purpose: To estimate the rate of disease control after conformal radiation therapy using reduced clinical target volume (CTV) margins and to determine factors that predict for tumor progression. Methods and Materials: Eighty-eight children (median age, 8.5 years; range, 3.2-17.6 years) received conformal or intensity modulated radiation therapy between 1998 and 2009. The study group included those prospectively treated from 1998 to 2003, using a 10-mm CTV, defined as the margin surrounding the solid and cystic tumor targeted to receive the prescription dose of 54 Gy. The CTV margin was subsequently reduced after 2003, yielding 2 groups of patients: those treated with a CTV margin greater than 5 mm (n=26) and those treated with a CTV margin less than or equal to 5 mm (n=62). Disease progression was estimated on the basis of additional variables including sex, race, extent of resection, tumor interventions, target volume margins, and frequency of weekly surveillance magnetic resonance (MR) imaging during radiation therapy. Median follow-up was 5 years. Results: There was no difference between progression-free survival rates based on CTV margins (>5 mm vs ≤5 mm) at 5 years (88.1% ± 6.3% vs 96.2% ± 4.4% [P=.6386]). There were no differences based on planning target volume (PTV) margins (or combined CTV plus PTV margins). The PTV was systematically reduced from 5 to 3 mm during the time period of the study. Factors predictive of superior progression-free survival included Caucasian race (P=.0175), no requirement for cerebrospinal fluid shunting (P=.0066), and number of surveillance imaging studies during treatment (P=.0216). Patients whose treatment protocol included a higher number of weekly surveillance MR imaging evaluations had a lower rate of tumor progression. Conclusions: These results suggest that targeted volume reductions for radiation therapy using smaller margins are feasible and safe but require careful monitoring. We are currently investigating

  11. Internal rotor friction instability

    Science.gov (United States)

    Walton, J.; Artiles, A.; Lund, J.; Dill, J.; Zorzi, E.

    1990-01-01

    The analytical developments and experimental investigations performed in assessing the effect of internal friction on rotor systems dynamic performance are documented. Analytical component models for axial splines, Curvic splines, and interference fit joints commonly found in modern high speed turbomachinery were developed. Rotor systems operating above a bending critical speed were shown to exhibit unstable subsynchronous vibrations at the first natural frequency. The effect of speed, bearing stiffness, joint stiffness, external damping, torque, and coefficient of friction, was evaluated. Testing included material coefficient of friction evaluations, component joint quantity and form of damping determinations, and rotordynamic stability assessments. Under conditions similar to those in the SSME turbopumps, material interfaces experienced a coefficient of friction of approx. 0.2 for lubricated and 0.8 for unlubricated conditions. The damping observed in the component joints displayed nearly linear behavior with increasing amplitude. Thus, the measured damping, as a function of amplitude, is not represented by either linear or Coulomb friction damper models. Rotordynamic testing of an axial spline joint under 5000 in.-lb of static torque, demonstrated the presence of an extremely severe instability when the rotor was operated above its first flexible natural frequency. The presence of this instability was predicted by nonlinear rotordynamic time-transient analysis using the nonlinear component model developed under this program. Corresponding rotordynamic testing of a shaft with an interference fit joint demonstrated the presence of subsynchronous vibrations at the first natural frequency. While subsynchronous vibrations were observed, they were bounded and significantly lower in amplitude than the synchronous vibrations.

  12. Benefits of expressive writing in reducing test anxiety: A randomized controlled trial in Chinese samples.

    Science.gov (United States)

    Shen, Lujun; Yang, Lei; Zhang, Jing; Zhang, Meng

    2018-01-01

    To explore the effect of expressive writing of positive emotions on test anxiety among senior-high-school students. The Test Anxiety Scale (TAS) was used to assess the anxiety level of 200 senior-high-school students. Seventy-five students with high anxiety were recruited and divided randomly into experimental and control groups. Each day for 30 days, the experimental group engaged in 20 minutes of expressive writing of positive emotions, while the control group was asked to merely write down their daily events. A second test was given after the month-long experiment to analyze whether there had been a reduction in anxiety among the sample. Quantitative data was obtained from TAS scores. The NVivo10.0 software program was used to examine the frequency of particular word categories used in participants' writing manuscripts. Senior-high-school students indicated moderate to high test anxiety. There was a significant difference in post-test results (P 0.05). Students' writing manuscripts were mainly encoded on five code categories: cause, anxiety manifestation, positive emotion, insight and evaluation. There was a negative relation between positive emotion, insight codes and test anxiety. There were significant differences in the positive emotion, anxiety manifestation, and insight code categories between the first 10 days' manuscripts and the last 10 days' ones. Long-term expressive writing of positive emotions appears to help reduce test anxiety by using insight and positive emotion words for Chinese students. Efficient and effective intervention programs to ease test anxiety can be designed based on this study.

  13. Analytical control of reducing agents on uranium/plutonium partitioning at purex process

    International Nuclear Information System (INIS)

    Araujo, Izilda da Cruz de

    1995-01-01

    Spectrophotometric methods for uranium (IV), hydrazine (N 2 H 4 ) and its decomposition product hydrazoic acid(HN 3 ), and hydroxylamine (NH 2 OH) determinations were developed aiming their applications for the process control of CELESTE I installation at IPEN/CNEN-SP. These compounds are normally present in the U/Pu partitioning phase of the spent nuclear treatment via PUREX process. The direct spectrophotometry was used for uranium (IV) analysis in nitric acid-hydrazine solutions based on the absorption measurement at 648 nm. The azomethine compound formed by reaction of hydrazine and p-dimethylamine benzaldehyde with maximum absorption at 457 nm was the basis for the specific analytical method for hydrazine determination. The hydrazoic acid analysis was performed indirectly by its conversion into ferric azide complex with maximum absorption at 465 nm. The hydroxylamine detection was accomplished based on its selective oxidation to nitrous acid which is easily analyzed by the reaction with Griess reagent. The resulted azocompound gas a maximum absorption at 520 nm. The sensibility of 1,4x10 -6 M for U(IV) with 0,8% of precision, 1,6x10 -6 M for hydrazine with 0,8% of precision, 2,3x10 -6 M hydrazoic acid with 0,9% of precision and 2,5x10 -6 M for hydroxylamine with 0,8% of precision were achieved. The interference studies have shown that each reducing agent can be determined in the presence of each other without any interference. Uranium(VI) and plutonium have also shown no interference in these analysis. The established methods were adapted to run inside glove-boxes by using an optical fiber colorimetry and applied to process control of the CELESTE I installation. The results pointed out that the methods are reliable and safety in order to provide just-in-time information about process conditions. (author)

  14. Benefits of expressive writing in reducing test anxiety: A randomized controlled trial in Chinese samples.

    Directory of Open Access Journals (Sweden)

    Lujun Shen

    Full Text Available To explore the effect of expressive writing of positive emotions on test anxiety among senior-high-school students.The Test Anxiety Scale (TAS was used to assess the anxiety level of 200 senior-high-school students. Seventy-five students with high anxiety were recruited and divided randomly into experimental and control groups. Each day for 30 days, the experimental group engaged in 20 minutes of expressive writing of positive emotions, while the control group was asked to merely write down their daily events. A second test was given after the month-long experiment to analyze whether there had been a reduction in anxiety among the sample. Quantitative data was obtained from TAS scores. The NVivo10.0 software program was used to examine the frequency of particular word categories used in participants' writing manuscripts.Senior-high-school students indicated moderate to high test anxiety. There was a significant difference in post-test results (P 0.05. Students' writing manuscripts were mainly encoded on five code categories: cause, anxiety manifestation, positive emotion, insight and evaluation. There was a negative relation between positive emotion, insight codes and test anxiety. There were significant differences in the positive emotion, anxiety manifestation, and insight code categories between the first 10 days' manuscripts and the last 10 days' ones.Long-term expressive writing of positive emotions appears to help reduce test anxiety by using insight and positive emotion words for Chinese students. Efficient and effective intervention programs to ease test anxiety can be designed based on this study.

  15. Do walking strategies to increase physical activity reduce reported sitting in workplaces: a randomized control trial

    Directory of Open Access Journals (Sweden)

    Burton Nicola W

    2009-07-01

    Full Text Available Abstract Background Interventions designed to increase workplace physical activity may not automatically reduce high volumes of sitting, a behaviour independently linked to chronic diseases such as obesity and type II diabetes. This study compared the impact two different walking strategies had on step counts and reported sitting times. Methods Participants were white-collar university employees (n = 179; age 41.3 ± 10.1 years; 141 women, who volunteered and undertook a standardised ten-week intervention at three sites. Pre-intervention step counts (Yamax SW-200 and self-reported sitting times were measured over five consecutive workdays. Using pre-intervention step counts, employees at each site were randomly allocated to a control group (n = 60; maintain normal behaviour, a route-based walking group (n = 60; at least 10 minutes sustained walking each workday or an incidental walking group (n = 59; walking in workday tasks. Workday step counts and reported sitting times were re-assessed at the beginning, mid- and endpoint of intervention and group mean± SD steps/day and reported sitting times for pre-intervention and intervention measurement points compared using a mixed factorial ANOVA; paired sample-t-tests were used for follow-up, simple effect analyses. Results A significant interactive effect (F = 3.5; p t = 3.9, p t = 2.5, p Conclusion Compared to controls, both route and incidental walking increased physical activity in white-collar employees. Our data suggests that workplace walking, particularly through incidental movement, also has the potential to decrease employee sitting times, but there is a need for on-going research using concurrent and objective measures of sitting, standing and walking.

  16. Benefits of expressive writing in reducing test anxiety: A randomized controlled trial in Chinese samples

    Science.gov (United States)

    Zhang, Jing; Zhang, Meng

    2018-01-01

    Purpose To explore the effect of expressive writing of positive emotions on test anxiety among senior-high-school students. Methods The Test Anxiety Scale (TAS) was used to assess the anxiety level of 200 senior-high-school students. Seventy-five students with high anxiety were recruited and divided randomly into experimental and control groups. Each day for 30 days, the experimental group engaged in 20 minutes of expressive writing of positive emotions, while the control group was asked to merely write down their daily events. A second test was given after the month-long experiment to analyze whether there had been a reduction in anxiety among the sample. Quantitative data was obtained from TAS scores. The NVivo10.0 software program was used to examine the frequency of particular word categories used in participants’ writing manuscripts. Results Senior-high-school students indicated moderate to high test anxiety. There was a significant difference in post-test results (P 0.05). Students’ writing manuscripts were mainly encoded on five code categories: cause, anxiety manifestation, positive emotion, insight and evaluation. There was a negative relation between positive emotion, insight codes and test anxiety. There were significant differences in the positive emotion, anxiety manifestation, and insight code categories between the first 10 days’ manuscripts and the last 10 days’ ones. Conclusions Long-term expressive writing of positive emotions appears to help reduce test anxiety by using insight and positive emotion words for Chinese students. Efficient and effective intervention programs to ease test anxiety can be designed based on this study. PMID:29401473

  17. Original sound compositions reduce anxiety in emergency department patients: a randomised controlled trial.

    Science.gov (United States)

    Weiland, Tracey J; Jelinek, George A; Macarow, Keely E; Samartzis, Philip; Brown, David M; Grierson, Elizabeth M; Winter, Craig

    2011-12-19

    To determine whether emergency department (ED) patients' self-rated levels of anxiety are affected by exposure to purpose-designed music or sound compositions with and without the audio frequencies of embedded binaural beat. Randomised controlled trial in an ED between 1 February 2010 and 14 April 2010 among a convenience sample of adult patients who were rated as category 3 on the Australasian Triage Scale. All interventions involved listening to soundtracks of 20 minutes' duration that were purpose-designed by composers and sound-recording artists. Participants were allocated at random to one of five groups: headphones and iPod only, no soundtrack (control group); reconstructed ambient noise simulating an ED but free of clear verbalisations; electroacoustic musical composition; composed non-musical soundtracks derived from audio field recordings obtained from natural and constructed settings; sound composition of audio field recordings with embedded binaural beat. All soundtracks were presented on an iPod through headphones. Patients and researchers were blinded to allocation until interventions were administered. State-trait anxiety was self-assessed before the intervention and state anxiety was self-assessed again 20 minutes after the provision of the soundtrack. Spielberger State-Trait Anxiety Inventory. Of 291 patients assessed for eligibility, 170 patients completed the pre-intervention anxiety self-assessment and 169 completed the post-intervention assessment. Significant decreases (all P beats (43; 37) when compared with those allocated to receive simulated ED ambient noise (40; 41) or headphones only (44; 44). In moderately anxious ED patients, state anxiety was reduced by 10%-15% following exposure to purpose-designed sound interventions. Australian New Zealand Clinical Trials Registry ACTRN 12608000444381.

  18. Association of reduced zinc status with poor glycemic control in individuals with type 2 diabetes mellitus.

    Science.gov (United States)

    Bandeira, Verônica da Silva; Pires, Liliane Viana; Hashimoto, Leila Leiko; Alencar, Luciane Luca de; Almondes, Kaluce Gonçalves Sousa; Lottenberg, Simão Augusto; Cozzolino, Silvia Maria Franciscato

    2017-12-01

    This study evaluated the relationship between the zinc-related nutritional status and glycemic and insulinemic markers in individuals with type 2 diabetes mellitus (T2DM). A total of 82 individuals with T2DM aged between 29 and 59 years were evaluated. The concentration of zinc in the plasma, erythrocytes, and urine was determined by the flame atomic absorption spectrometry method. Dietary intake was assessed using a 3-day 24-h recall. In addition, concentrations of serum glucose, glycated hemoglobin percentage, total cholesterol and fractions, triglycerides, and serum insulin were determined. The insulin resistance index (HOMA-IR) and β-cell function (HOMA- β) were calculated. The markers of zinc status (plasma: 83.3±11.9μg/dL, erythrocytes: 30.1±4.6μg/g Hb, urine: 899.1±622.4μg Zn/24h, and dietary: 9.9±0.8mg/day) were classified in tertiles and compared to insulinemic and glycemic markers. The results showed that lower zinc concentrations in plasma and erythrocytes, as well as its high urinary excretion, were associated with higher percentages of glycated hemoglobin, reflecting a worse glycemic control in individuals with T2DM (pzinc levels and glycated hemoglobin percentage (r=-0.325, p=0.003), and a positive correlation between urinary zinc excretion and glycemia (r=0.269, p=0.016), glycated hemoglobin percentage (r=0.318, p=0.004) and HOMA-IR (r=0.289, p=0.009). According to our study results, conclude that T2DM individuals with reduced zinc status exhibited poor glycemic control. Copyright © 2017 Elsevier GmbH. All rights reserved.

  19. Pomegranate Intake Protects Against Genomic Instability Induced by Medical X-rays In Vivo in Mice.

    Science.gov (United States)

    Nallanthighal, Sameera; Shirode, Amit B; Judd, Julius A; Reliene, Ramune

    2016-01-01

    Ionizing radiation (IR) is a well-documented human carcinogen. The increased use of IR in medical procedures has doubled the annual radiation dose and may increase cancer risk. Genomic instability is an intermediate lesion in IR-induced cancer. We examined whether pomegranate extract (PE) suppresses genomic instability induced by x-rays. Mice were treated orally with PE and exposed to an x-ray dose of 2 Gy. PE intake suppressed x-ray-induced DNA double-strand breaks (DSBs) in peripheral blood and chromosomal damage in bone marrow. We hypothesized that PE-mediated protection against x-ray-induced damage may be due to the upregulation of DSB repair and antioxidant enzymes and/or increase in glutathione (GSH) levels. We found that expression of DSB repair genes was not altered (Nbs1 and Rad50) or was reduced (Mre11, DNA-PKcs, Ku80, Rad51, Rad52 and Brca2) in the liver of PE-treated mice. Likewise, mRNA levels of antioxidant enzymes were reduced (Gpx1, Cat, and Sod2) or were not altered (HO-1 and Sod1) as a function of PE treatment. In contrast, PE-treated mice with and without IR exposure displayed higher hepatic GSH concentrations than controls. Thus, ingestion of pomegranate polyphenols is associated with inhibition of x-ray-induced genomic instability and elevated GSH, which may reduce cancer risk.

  20. Options for reducing food waste by ‘Quality Controlled Logistics’ using intelligent packaging along the supply chain

    NARCIS (Netherlands)

    Heising, J.K.; Claassen, G.D.H.; Dekker, M.

    2017-01-01

    Optimizing supply chain management can help to reduce food waste. This article describes how intelligent packaging can be used to reduce food waste when used in supply chain management based on Quality Controlled Logistics (QCL). Intelligent packaging senses compounds in the package that correlate

  1. Dynamical Instability and Soliton Concept

    International Nuclear Information System (INIS)

    Kartavenko, V.G.

    1994-01-01

    The problem of dynamical instability and clustering (stable fragments formation) in a breakup of excited nuclear systems are considered from the points of view of the soliton concept. It is noted that the volume (spinodal) instability can be associated with nonlinear terms, and the surface (Rayleigh-Taylor type) instability, with the dispersion terms in the evolution equations. The spinodal instability and the Rayleigh-Taylor instability may compensate each other and lead to stable quasi-soliton type objects. The simple analytical model is presented to illustrate this physical picture. The time evolution of an initially compressed cold nuclear system is analysed in the framework of the inverse mean-field method. It is demonstrated that the nonlinearity and dispersion terms of the evolution equations can lead to clusterization in the final channel. 8 p

  2. Beam instability Workshop - plenary sessions

    International Nuclear Information System (INIS)

    2001-01-01

    The purpose of this workshop was to provide a review of the mechanisms of limiting beam instabilities, their cures, including feedback, and beam measurement for synchrotron radiation light sources. 12 plenary sessions took place whose titles are: 1) challenging brilliance and lifetime issues with increasing currents; 2) limiting instabilities in multibunch; 3) experience from high currents in B factories; 4) longitudinal dynamics in high intensity/bunch; 5) Transverse instabilities for high intensity/bunch; 6) working group introduction from ESRF experience; 7) impedance modelling: simulations, minimization; 8) report on the broadband impedance measurements and modelling workshop; 9) feedback systems for synchrotron light sources; 10) beam instabilities diagnostics; 11) harmonic cavities: the pros and cons; and 12) experimental study of fast beam-ion instabilities at PLS. This document gathers the 12 articles that were presented during these sessions

  3. Beam instability Workshop - plenary sessions

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    The purpose of this workshop was to provide a review of the mechanisms of limiting beam instabilities, their cures, including feedback, and beam measurement for synchrotron radiation light sources. 12 plenary sessions took place whose titles are: 1) challenging brilliance and lifetime issues with increasing currents; 2) limiting instabilities in multibunch; 3) experience from high currents in B factories; 4) longitudinal dynamics in high intensity/bunch; 5) Transverse instabilities for high intensity/bunch; 6) working group introduction from ESRF experience; 7) impedance modelling: simulations, minimization; 8) report on the broadband impedance measurements and modelling workshop; 9) feedback systems for synchrotron light sources; 10) beam instabilities diagnostics; 11) harmonic cavities: the pros and cons; and 12) experimental study of fast beam-ion instabilities at PLS. This document gathers the 12 articles that were presented during these sessions.

  4. Electron/electron acoustic instability

    International Nuclear Information System (INIS)

    Gary, S.P.

    1987-01-01

    The electron acoustic wave becomes a normal mode of an unmagnetized collisionless plasma in the presence of two electron components with similar densities, but strongly disparate temperatures. The characteristic frequency of this mode is the plasma frequency of the cooler electron component. If these two electron components have a relative drift speed several times the thermal speed of the cooler component, the electron/electron acoustic instability may arise. This paper describes the parametric dependences of the threshold drift speed and maximum growth rate of this instability, and compares these with the same properties of the electron/ion acoustic instability. Under the condition of zero current, the electron/ion acoustic instability typically has the lower threshold drift speed, so that observation of the electron/electron acoustic instability is a strong indication of the presence of an electrical current in the plasma

  5. Feedback to suppress beam instabilities in future proton rings

    International Nuclear Information System (INIS)

    Lambertson, G.R.

    1985-05-01

    Criteria for the design of feedback systems to suppress coherent beam instabilities are presented. These address starting amplitudes, diffusion from noise during damping or long storage, and choice of kicker. As a model for future accelerators, specifications of the proposed 20 TeV SSC are used to calculate parameters of systems to control expected instabilities. A scenario and hardware to stabilize the transverse mode-coupling instability is examined. The scale of the systems is large but not out of scale with the large ring. 9 refs., 4 tabs

  6. Thermal shrinkage for shoulder instability.

    Science.gov (United States)

    Toth, Alison P; Warren, Russell F; Petrigliano, Frank A; Doward, David A; Cordasco, Frank A; Altchek, David W; O'Brien, Stephen J

    2011-07-01

    Thermal capsular shrinkage was popular for the treatment of shoulder instability, despite a paucity of outcomes data in the literature defining the indications for this procedure or supporting its long-term efficacy. The purpose of this study was to perform a clinical evaluation of radiofrequency thermal capsular shrinkage for the treatment of shoulder instability, with a minimum 2-year follow-up. From 1999 to 2001, 101 consecutive patients with mild to moderate shoulder instability underwent shoulder stabilization surgery with thermal capsular shrinkage using a monopolar radiofrequency device. Follow-up included a subjective outcome questionnaire, discussion of pain, instability, and activity level. Mean follow-up was 3.3 years (range 2.0-4.7 years). The thermal capsular shrinkage procedure failed due to instability and/or pain in 31% of shoulders at a mean time of 39 months. In patients with unidirectional anterior instability and those with concomitant labral repair, the procedure proved effective. Patients with multidirectional instability had moderate success. In contrast, four of five patients with isolated posterior instability failed. Thermal capsular shrinkage has been advocated for the treatment of shoulder instability, particularly mild to moderate capsular laxity. The ease of the procedure makes it attractive. However, our retrospective review revealed an overall failure rate of 31% in 80 patients with 2-year minimum follow-up. This mid- to long-term cohort study adds to the literature lacking support for thermal capsulorrhaphy in general, particularly posterior instability. The online version of this article (doi:10.1007/s11420-010-9187-7) contains supplementary material, which is available to authorized users.

  7. Expression of Arabidopsis hexokinase in citrus guard cells controls stomatal aperture and reduces transpiration

    Directory of Open Access Journals (Sweden)

    Nitsan eLugassi

    2015-12-01

    Full Text Available Hexokinase (HXK is a sugar-phosphorylating enzyme involved in sugar-sensing. It has recently been shown that HXK in guard cells mediates stomatal closure and coordinates photosynthesis with transpiration in the annual species tomato and Arabidopsis. To examine the role of HXK in the control of the stomatal movement of perennial plants, we generated citrus plants that express Arabidopsis HXK1 (AtHXK1 under KST1, a guard cell-specific promoter. The expression of KST1 in the guard cells of citrus plants has been verified using GFP as a reporter gene. The expression of AtHXK1 in the guard cells of citrus reduced stomatal conductance and transpiration with no negative effect on the rate of photosynthesis, leading to increased water-use efficiency. The effects of light intensity and humidity on stomatal behavior were examined in rooted leaves of the citrus plants. The optimal intensity of photosynthetically active radiation and lower humidity enhanced stomatal closure of AtHXK1-expressing leaves, supporting the role of sugar in the regulation of citrus stomata. These results suggest that HXK coordinates photosynthesis and transpiration and stimulates stomatal closure not only in annual species, but also in perennial species.

  8. Randomized controlled trial of relaxation music to reduce heart rate in patients undergoing cardiac CT

    Energy Technology Data Exchange (ETDEWEB)

    Ng, Ming Yen [University of Toronto, Department of Medical Imaging, Toronto General Hospital, Toronto, ON (Canada); The University of Hong Kong, Queen Mary Hospital, Department of Diagnostic Radiology, Hong Kong (China); Karimzad, Yasser; Menezes, Ravi J.; Wintersperger, Bernd J.; Li, Qin; Forero, Julian; Paul, Narinder S.; Nguyen, Elsie T. [University of Toronto, Department of Medical Imaging, Toronto General Hospital, Toronto, ON (Canada)

    2016-10-15

    To evaluate the heart rate lowering effect of relaxation music in patients undergoing coronary CT angiography (CCTA), pulmonary vein CT (PVCT) and coronary calcium score CT (CCS). Patients were randomised to a control group (i.e. standard of care protocol) or to a relaxation music group (ie. standard of care protocol with music). The groups were compared for heart rate, radiation dose, image quality and dose of IV metoprolol. Both groups completed State-Trait Anxiety Inventory anxiety questionnaires to assess patient experience. One hundred and ninety-seven patients were recruited (61.9 % males); mean age 56y (19-86 y); 127 CCTA, 17 PVCT, 53 CCS. No significant difference in heart rate, radiation dose, image quality, metoprolol dose and anxiety scores. 86 % of patients enjoyed the music. 90 % of patients in the music group expressed a strong preference to have music for future examinations. The patient cohort demonstrated low anxiety levels prior to CT. Relaxation music in CCTA, PVCT and CCS does not reduce heart rate or IV metoprolol use. Patients showed low levels of anxiety indicating that anxiolytics may not have a significant role in lowering heart rate. Music can be used in cardiac CT to improve patient experience. (orig.)

  9. Randomized Controlled Trial Considering Varied Exercises for Reducing Proactive Memory Interference

    Directory of Open Access Journals (Sweden)

    Emily Frith

    2018-06-01

    Full Text Available We evaluated the effects of exercise on proactive memory interference. Study 1 (n = 88 employed a 15-min treadmill walking protocol, while Study 2 (n = 88 included a 15-min bout of progressive maximal exertion treadmill exercise. Each study included four distinct groups, in which groups of 22 participants each were randomly assigned to: (a exercise before memory encoding, (b a control group with no exercise, (c exercise during memory encoding, and (d exercise after memory encoding (i.e., during memory consolidation. We used the Rey Auditory Verbal Learning Test (RAVLT to assess proactive memory interference. In both studies, the group that exercised prior to memory encoding recalled the most words from list B (distractor list of the RAVLT, though group differences were not statistically significant for Study 1 (walking exercise (p = 0.521 or Study 2 (high-intensity exercise (p = 0.068. In this sample of young adults, high intensity exercise prior to memory encoding showed a non-significant tendency to attenuate impairments in recall attributable to proactive memory interference. Thus, future work with larger samples is needed to clarify potential beneficial effects of exercise for reducing proactive memory interference.

  10. Randomized Controlled Trial Considering Varied Exercises for Reducing Proactive Memory Interference.

    Science.gov (United States)

    Frith, Emily; Sng, Eveleen; Loprinzi, Paul D

    2018-06-11

    We evaluated the effects of exercise on proactive memory interference. Study 1 ( n = 88) employed a 15-min treadmill walking protocol, while Study 2 ( n = 88) included a 15-min bout of progressive maximal exertion treadmill exercise. Each study included four distinct groups, in which groups of 22 participants each were randomly assigned to: (a) exercise before memory encoding, (b) a control group with no exercise, (c) exercise during memory encoding, and (d) exercise after memory encoding (i.e., during memory consolidation). We used the Rey Auditory Verbal Learning Test (RAVLT) to assess proactive memory interference. In both studies, the group that exercised prior to memory encoding recalled the most words from list B (distractor list) of the RAVLT, though group differences were not statistically significant for Study 1 (walking exercise) ( p = 0.521) or Study 2 (high-intensity exercise) ( p = 0.068). In this sample of young adults, high intensity exercise prior to memory encoding showed a non-significant tendency to attenuate impairments in recall attributable to proactive memory interference. Thus, future work with larger samples is needed to clarify potential beneficial effects of exercise for reducing proactive memory interference.

  11. Four-wall turbine airfoil with thermal strain control for reduced cycle fatigue

    Science.gov (United States)

    Cambell, Christian X

    2013-09-17

    A turbine airfoil (20B) with a thermal expansion control mechanism that increases the airfoil camber (60, 61) under operational heating. The airfoil has four-wall geometry, including pressure side outer and inner walls (26, 28B), and suction side outer and inner walls (32, 34B). It has near-wall cooling channels (31F, 31A, 33F, 33A) between the outer and inner walls. A cooling fluid flow pattern (50C, 50W, 50H) in the airfoil causes the pressure side inner wall (28B) to increase in curvature under operational heating. The pressure side inner wall (28B) is thicker than walls (26, 34B) that oppose it in camber deformation, so it dominates them in collaboration with the suction side outer wall (32), and the airfoil camber increases. This reduces and relocates a maximum stress area (47) from the suction side outer wall (32) to the suction side inner wall (34B, 72) and the pressure side outer wall (26).

  12. Randomized controlled trial of relaxation music to reduce heart rate in patients undergoing cardiac CT

    International Nuclear Information System (INIS)

    Ng, Ming Yen; Karimzad, Yasser; Menezes, Ravi J.; Wintersperger, Bernd J.; Li, Qin; Forero, Julian; Paul, Narinder S.; Nguyen, Elsie T.

    2016-01-01

    To evaluate the heart rate lowering effect of relaxation music in patients undergoing coronary CT angiography (CCTA), pulmonary vein CT (PVCT) and coronary calcium score CT (CCS). Patients were randomised to a control group (i.e. standard of care protocol) or to a relaxation music group (ie. standard of care protocol with music). The groups were compared for heart rate, radiation dose, image quality and dose of IV metoprolol. Both groups completed State-Trait Anxiety Inventory anxiety questionnaires to assess patient experience. One hundred and ninety-seven patients were recruited (61.9 % males); mean age 56y (19-86 y); 127 CCTA, 17 PVCT, 53 CCS. No significant difference in heart rate, radiation dose, image quality, metoprolol dose and anxiety scores. 86 % of patients enjoyed the music. 90 % of patients in the music group expressed a strong preference to have music for future examinations. The patient cohort demonstrated low anxiety levels prior to CT. Relaxation music in CCTA, PVCT and CCS does not reduce heart rate or IV metoprolol use. Patients showed low levels of anxiety indicating that anxiolytics may not have a significant role in lowering heart rate. Music can be used in cardiac CT to improve patient experience. (orig.)

  13. Expression of Arabidopsis Hexokinase in Citrus Guard Cells Controls Stomatal Aperture and Reduces Transpiration.

    Science.gov (United States)

    Lugassi, Nitsan; Kelly, Gilor; Fidel, Lena; Yaniv, Yossi; Attia, Ziv; Levi, Asher; Alchanatis, Victor; Moshelion, Menachem; Raveh, Eran; Carmi, Nir; Granot, David

    2015-01-01

    Hexokinase (HXK) is a sugar-phosphorylating enzyme involved in sugar-sensing. It has recently been shown that HXK in guard cells mediates stomatal closure and coordinates photosynthesis with transpiration in the annual species tomato and Arabidopsis. To examine the role of HXK in the control of the stomatal movement of perennial plants, we generated citrus plants that express Arabidopsis HXK1 (AtHXK1) under KST1, a guard cell-specific promoter. The expression of KST1 in the guard cells of citrus plants has been verified using GFP as a reporter gene. The expression of AtHXK1 in the guard cells of citrus reduced stomatal conductance and transpiration with no negative effect on the rate of photosynthesis, leading to increased water-use efficiency. The effects of light intensity and humidity on stomatal behavior were examined in rooted leaves of the citrus plants. The optimal intensity of photosynthetically active radiation and lower humidity enhanced stomatal closure of AtHXK1-expressing leaves, supporting the role of sugar in the regulation of citrus stomata. These results suggest that HXK coordinates photosynthesis and transpiration and stimulates stomatal closure not only in annual species, but also in perennial species.

  14. Ignition target and laser-plasma instabilities

    International Nuclear Information System (INIS)

    Laffite, S.; Loiseau, P.

    2010-01-01

    For the first time indirect drive ignition targets have been designed with the constraint of limiting laser-plasma instabilities. The amplification of these instabilities is directly proportional to the luminous flux density, it means to the sizes of the focal spots too. This study shows that increasing the sizes of the focal spots does not reduce linear amplification gains in a proportional way because the global optimization of the target implies changes in hydrodynamical conditions that in turn have an impact on the value of the amplification gain. The design of the target is a 2-step approach: the first step aims at assuring a uniform irradiation and compression of the target. The first step requires information concerning the laser focusing spots, the dimensions of the hohlraum, the inert gas contained in it, the materials of the wall. The second step is an optimization approach whose aim is to reduce the risk of laser-plasmas instabilities. This optimization is made through simulations of the amplification gains of stimulated Raman and Brillouin backscattering. This method has allowed us to design an optimized target for a rugby-shaped hohlraum. (A.C.)

  15. Instability timescale for the inclination instability in the solar system

    Science.gov (United States)

    Zderic, Alexander; Madigan, Ann-Marie; Fleisig, Jacob

    2018-04-01

    The gravitational influence of small bodies is often neglected in the study of solar system dynamics. However, this is not always an appropriate assumption. For example, mutual secular torques between low mass particles on eccentric orbits can result in a self-gravity instability (`inclination instability'; Madigan & McCourt 2016). During the instability, inclinations increase exponentially, eccentricities decrease (detachment), and orbits cluster in argument of perihelion. In the solar system, the orbits of the most distant objects show all three of these characteristics (high inclination: Volk & Malhotra (2017), detachment: Delsanti & Jewitt (2006), and argument of perihelion clustering: Trujillo & Sheppard (2014)). The inclination instability is a natural explanation for these phenomena.Unfortunately, full N-body simulations of the solar system are unfeasible (N ≈ O(1012)), and the behavior of the instability depends on N, prohibiting the direct application of lower N simulations. Here we present the instability timescale's functional dependence on N, allowing us to extrapolate our simulation results to that appropriate for the solar system. We show that ~5 MEarth of small icy bodies in the Sedna region is sufficient for the inclination instability to occur in the outer solar system.

  16. The use of active breathing control (ABC) to reduce margin for breathing motion

    International Nuclear Information System (INIS)

    Wong, John W.; Sharpe, Michael B.; Jaffray, David A.; Kini, Vijay R.; Robertson, John M.; Stromberg, Jannifer S.; Martinez, Alavro A.

    1999-01-01

    Purpose: For tumors in the thorax and abdomen, reducing the treatment margin for organ motion due to breathing reduces the volume of normal tissues that will be irradiated. A higher dose can be delivered to the target, provided that the risk of marginal misses is not increased. To ensure safe margin reduction, we investigated the feasibility of using active breathing control (ABC) to temporarily immobilize the patient's breathing. Treatment planning and delivery can then be performed at identical ABC conditions with minimal margin for breathing motion. Methods and Materials: An ABC apparatus is constructed consisting of 2 pairs of flow monitor and scissor valve, 1 each to control the inspiration and expiration paths to the patient. The patient breathes through a mouth-piece connected to the ABC apparatus. The respiratory signal is processed continuously, using a personal computer that displays the changing lung volume in real-time. After the patient's breathing pattern becomes stable, the operator activates ABC at a preselected phase in the breathing cycle. Both valves are then closed to immobilize breathing motion. Breathing motion of 12 patients were held with ABC to examine their acceptance of the procedure. The feasibility of applying ABC for treatment was tested in 5 patients by acquiring volumetric scans with a spiral computed tomography (CT) scanner during active breath-hold. Two patients had Hodgkin's disease, 2 had metastatic liver cancer, and 1 had lung cancer. Two intrafraction ABC scans were acquired at the same respiratory phase near the end of normal or deep inspiration. An additional ABC scan near the end of normal expiration was acquired for 2 patients. The ABC scans were also repeated 1 week later for a Hodgkin's patient. In 1 liver patient, ABC scans were acquired at 7 different phases of the breathing cycle to facilitate examination of the liver motion associated with ventilation. Contours of the lungs and livers were outlined when applicable

  17. Experimental Evaluation of a Mixed Controller That Amplifies Spatial Errors and Reduces Timing Errors

    Directory of Open Access Journals (Sweden)

    Laura Marchal-Crespo

    2017-06-01

    Full Text Available Research on motor learning suggests that training with haptic guidance enhances learning of the timing components of motor tasks, whereas error amplification is better for learning the spatial components. We present a novel mixed guidance controller that combines haptic guidance and error amplification to simultaneously promote learning of the timing and spatial components of complex motor tasks. The controller is realized using a force field around the desired position. This force field has a stable manifold tangential to the trajectory that guides subjects in velocity-related aspects. The force field has an unstable manifold perpendicular to the trajectory, which amplifies the perpendicular (spatial error. We also designed a controller that applies randomly varying, unpredictable disturbing forces to enhance the subjects’ active participation by pushing them away from their “comfort zone.” We conducted an experiment with thirty-two healthy subjects to evaluate the impact of four different training strategies on motor skill learning and self-reported motivation: (i No haptics, (ii mixed guidance, (iii perpendicular error amplification and tangential haptic guidance provided in sequential order, and (iv randomly varying disturbing forces. Subjects trained two motor tasks using ARMin IV, a robotic exoskeleton for upper limb rehabilitation: follow circles with an ellipsoidal speed profile, and move along a 3D line following a complex speed profile. Mixed guidance showed no detectable learning advantages over the other groups. Results suggest that the effectiveness of the training strategies depends on the subjects’ initial skill level. Mixed guidance seemed to benefit subjects who performed the circle task with smaller errors during baseline (i.e., initially more skilled subjects, while training with no haptics was more beneficial for subjects who created larger errors (i.e., less skilled subjects. Therefore, perhaps the high functional

  18. Brief intervention to reduce risky drinking in pregnancy: study protocol for a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Wilson Graeme B

    2012-09-01

    Full Text Available Abstract Background Risky drinking in pregnancy by UK women is likely to result in many alcohol-exposed pregnancies. Studies from the USA suggest that brief intervention has promise for alcohol risk reduction in antenatal care. However, further research is needed to establish whether this evidence from the USA is applicable to the UK. This pilot study aims to investigate whether pregnant women can be recruited and retained in a randomized controlled trial of brief intervention aimed at reducing risky drinking in women receiving antenatal care. Methods The trial will rehearse the parallel-group, non-blinded design and procedures of a subsequent definitive trial. Over 8 months, women aged 18 years and over (target number 2,742 attending their booking appointment with a community midwife (n = 31 in north-east England will be screened for alcohol consumption using the consumption questions of the Alcohol Use Disorders Identification Test (AUDIT-C. Those screening positive, without a history of substance use or alcohol dependence, with no pregnancy complication, and able to give informed consent, will be invited to participate in the trial (target number 120. Midwives will be randomized in a 1:1 ratio to deliver either treatment as usual (control or structured brief advice and referral for a 20-minute motivational interviewing session with an alcohol health worker (intervention. As well as demographic and health information, baseline measures will include two 7-day time line follow-back questionnaires and the EuroQoL EQ-5D-3 L questionnaire. Measures will be repeated in telephone follow-ups in the third trimester and at 6 months post-partum, when a questionnaire on use of National Health Service and social care resources will also be completed. Information on pregnancy outcomes and stillbirths will be accessed from central health service records before the follow-ups. Primary outcomes will be rates of eligibility, recruitment, intervention

  19. Bifurcation theory for toroidal MHD instabilities

    International Nuclear Information System (INIS)

    Maschke, E.K.; Morros Tosas, J.; Urquijo, G.

    1992-01-01

    Using a general representation of magneto-hydrodynamics in terms of stream functions and potentials, proposed earlier, a set of reduced MHD equations for the case of toroidal geometry had been derived by an appropriate ordering with respect to the inverse aspect ratio. When all dissipative terms are neglected in this reduced system, it has the same linear stability limits as the full ideal MHD equations, to the order considered. When including resistivity, thermal conductivity and viscosity, we can apply bifurcation theory to investigate nonlinear stationary solution branches related to various instabilities. In particular, we show that a stationary solution of the internal kink type can be found

  20. Functional Instability of the Ankle Joint: Etiopathogenesis

    Directory of Open Access Journals (Sweden)

    Aydan ÖRSÇELİK

    2016-09-01

    Full Text Available Ankle sprain is one of the most common sports injuries. Chronic ankle instability is a common complication of ankle sprains. Two causes of chronic ankle instability are mechanical instability and functional instability. It is important to understand functional instability etiopathogenesis of the ankle joint in order to guide diagnosis and treatment. This article aims to understand the etiopathogenesis of functional ankle instability.

  1. Cashew consumption reduces total and LDL cholesterol: a randomized, crossover, controlled-feeding trial.

    Science.gov (United States)

    Mah, Eunice; Schulz, Jacqueline A; Kaden, Valerie N; Lawless, Andrea L; Rotor, Jose; Mantilla, Libertie B; Liska, DeAnn J

    2017-05-01

    Background: Cashews are the third most-consumed tree nut in the United States and are abundant with monounsaturated fatty acids and polyunsaturated fatty acids, which are associated with reduced cardiovascular disease risk. Although a qualified Food and Drug Administration health claim exists for nuts and heart health, cashews have been exempt from its use because cashews exceed the disqualifying amount of saturated fatty acids. Approximately one-third of the saturated fat in cashews is stearic acid, which is relatively neutral on blood lipids, thereby suggesting that cashews could have effects that are similar to those of other nuts. However, clinical data on cashews and blood lipids have been limited. Objective: We investigated the effect of reasonable intakes of cashews on serum lipids in adults with or at risk of high LDL cholesterol. Design: In a randomized, crossover, isocaloric, controlled-feeding study, 51 men and women (aged 21-73 y) with a median LDL-cholesterol concentration of 159 mg/dL (95% CI: 146, 165 mg/dL) at screening consumed typical American diets with cashews (28-64 g/d; 50% of kilocalories from carbohydrate, 18% of kilocalories from protein, and 32% of kilocalories from total fat) or potato chips (control; 54% of kilocalories from carbohydrate, 18% of kilocalories from protein, and 29% of kilocalories from total fat) for 28 d with a ≥2-wk washout period. Results: Consumption of the cashew diet resulted in a significantly greater median change from baseline (compared with the control, all P cholesterol [-3.9% (95% CI: -9.3%, 1.7%) compared with 0.8% (95% CI: -1.5%, 4.5%), respectively], LDL cholesterol [-4.8% (95% CI: -12.6%, 3.1%) compared with 1.2% (95% CI: -2.3%, 7.8%), respectively], non-HDL cholesterol [-5.3% (95% CI: -8.6%, 2.1%) compared with 1.7% (95% CI: -0.9%, 5.6%), respectively], and the total-cholesterol:HDL-cholesterol ratio [-0.0% (95% CI: -4.3%, 4.8%) compared with 3.4% (95% CI: 0.6%, 5.2%), respectively]. There were no

  2. Evaluation of the instability problems in rock slopes surrounding historical Safranbolu by kinematic analysis

    Directory of Open Access Journals (Sweden)

    İnan Keskin

    2017-10-01

    Full Text Available Safranbolu which has high probability for slope-induced disasters is a very worthwhile settlement for our country and also for the world with its historical and cultural heritage. Finding out potential hazards that may affect the wealth of this world heritage city is very crucial. The historic Safranbolu is surrounded by very steep rock slopes, and occasionally instability occurs in the rock mass that forms these slopes. The rock blocks that are relaesed in various causes and shapes can damage the historic town living spaces by creating a source for the rock fallings and moving down the slope in these very steep slopes. The rock slopes were evaluated by kinematic analysis in order to reduce the mentioned damages and to reveal potential hazards. In the study, characteristics of mass that causes rock fallings are analysed, kinematic controlled instability types are determined considering the obtained data and characteristic of slopes.

  3. The Rayleigh-Taylor instability in inertial fusion, astrophysical plasma and flames

    International Nuclear Information System (INIS)

    Bychkov, V; Modestov, M; Akkerman, V; Eriksson, L-E

    2007-01-01

    Previous results are reviewed and new results are presented on the Rayleigh-Taylor instability in inertial confined fusion, flames and supernovae including gravitational and thermonuclear explosion mechanisms. The instability couples micro-scale plasma effects to large-scale hydrodynamic phenomena. In inertial fusion the instability reduces target compression. In supernovae the instability produces large-scale convection, which determines the fate of the star. The instability is often accompanied by mass flux through the unstable interface, which may have either a stabilizing or a destabilizing influence. Destabilization happens due to the Darrieus-Landau instability of a deflagration front. Still, it is unclear whether the instabilities lead to well-organized large-scale structures (bubbles) or to relatively isotropic turbulence (mixing layer)

  4. Reduced-order model based active disturbance rejection control of hydraulic servo system with singular value perturbation theory.

    Science.gov (United States)

    Wang, Chengwen; Quan, Long; Zhang, Shijie; Meng, Hongjun; Lan, Yuan

    2017-03-01

    Hydraulic servomechanism is the typical mechanical/hydraulic double-dynamics coupling system with the high stiffness control and mismatched uncertainties input problems, which hinder direct applications of many advanced control approaches in the hydraulic servo fields. In this paper, by introducing the singular value perturbation theory, the original double-dynamics coupling model of the hydraulic servomechanism was reduced to a integral chain system. So that, the popular ADRC (active disturbance rejection control) technology could be directly applied to the reduced system. In addition, the high stiffness control and mismatched uncertainties input problems are avoided. The validity of the simplified model is analyzed and proven theoretically. The standard linear ADRC algorithm is then developed based on the obtained reduced-order model. Extensive comparative co-simulations and experiments are carried out to illustrate the effectiveness of the proposed method. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  5. Hydroxychloroquine effectiveness in reducing symptoms of hand osteoarthritis (HERO): study protocol for a randomized controlled trial

    Science.gov (United States)

    2013-01-01

    Background Osteoarthritis (OA) is the most common type of arthritis, causing significant joint pain and disability. It is already a major cause of healthcare expenditure and its incidence will further increase with the ageing population. Current treatments for OA have major limitations and new analgesic treatments are needed. Synovitis is prevalent in OA and is associated with pain. Hydroxychloroquine is used in routine practice for treating synovitis in inflammatory arthritides, such as rheumatoid arthritis. We propose that treating patients with symptomatic hand OA with hydroxychloroquine will be a practical and safe treatment to reduce synovitis and pain. Methods/design HERO is an investigator-initiated, multicentre, randomized, double-blind, placebo-controlled trial. A total of 252 subjects with symptomatic hand OA will be recruited across primary and secondary care sites in the UK and randomized on a 1:1 basis to active treatment or placebo for 12 months. Daily medication dose will range from 200 to 400 mg according to ideal body weight. The primary endpoint is change in average hand pain during the previous two weeks (measured on a numerical rating scale (NRS)) between baseline and six months. Secondary endpoints include other self-reported pain, function and quality-of-life measures and radiographic structural change at 12 months. A health economics analysis will also be performed. An ultrasound substudy will be conducted to examine baseline levels of synovitis. Linear and logistic regression will be used to compare changes between groups using univariable and multivariable modelling analyses. All analyses will be conducted on an intention-to-treat basis. Discussion The HERO trial is designed to examine whether hydroxychloroquine is an effective analgesic treatment for OA and whether it provides any long-term structural benefit. The ultrasound substudy will address whether baseline synovitis is a predictor of therapeutic response. This will potentially

  6. In Situ Microbial Community Control of the Stability of Bio-reduced Uranium

    International Nuclear Information System (INIS)

    Baldwin, Brett R.; Peacock, Aaron D.; Resch, Charles T.; Arntzen, Evan; Smithgall, Amanda N.; Pfiffner, Susan; Gan, M.; McKinley, James P.; Long, Philip E.; White, David C.

    2008-01-01

    In aerobic aquifers typical of many Department of Energy (DOE) legacy waste sites, uranium is present in the oxidized U(VI) form which is more soluble and thus more mobile. Field experiments at the Old Rifle UMTRA site have demonstrated that biostimulation by electron donor addition (acetate) promotes biological U(VI) reduction (2). However, U(VI) reduction is reversible and oxidative dissolution of precipitated U(IV) after the cessation of electron donor addition remains a critical issue for the application of biostimulation as a treatment technology. Despite the potential for oxidative dissolution, field experiments at the Old Rifle site have shown that rapid reoxidation of bio-reduced uranium does not occur and U(VI) concentrations can remain at approximately 20% of background levels for more than one year. The extent of post-amendment U(VI) removal and the maintenance of bioreduced uranium may result from many factors including U(VI) sorption to iron-containing mineral phases, generation of H2S or FeS0.9, or the preferential sorption of U(VI) by microbial cells or biopolymers, but the processes controlling the reduction and in situ reoxidation rates are not known. To investigate the role of microbial community composition in the maintenance of bioreduced uranium, in-well sediment incubators (ISIs) were developed allowing field deployment of amended and native sediments during on-going experiments at the site. Field deployment of the ISIs allows expedient interrogation of microbial community response to field environmental perturbations and varying geochemical conditions.

  7. In Situ Microbial Community Control of the Stability of Bio-reduced Uranium

    Energy Technology Data Exchange (ETDEWEB)

    Baldwin, Brett, R.; Peacock, Aaron, D.; Resch, Charles, T.; Arntzen, Evan; Smithgall, Amanda, N.; Pfiffner, Susan; Gan, M.; McKinley, James, P.; Long, Philip, E.; White, David, C.

    2008-03-28

    In aerobic aquifers typical of many Department of Energy (DOE) legacy waste sites, uranium is present in the oxidized U(VI) form which is more soluble and thus more mobile. Field experiments at the Old Rifle UMTRA site have demonstrated that biostimulation by electron donor addition (acetate) promotes biological U(VI) reduction (2). However, U(VI) reduction is reversible and oxidative dissolution of precipitated U(IV) after the cessation of electron donor addition remains a critical issue for the application of biostimulation as a treatment technology. Despite the potential for oxidative dissolution, field experiments at the Old Rifle site have shown that rapid reoxidation of bio-reduced uranium does not occur and U(VI) concentrations can remain at approximately 20% of background levels for more than one year. The extent of post-amendment U(VI) removal and the maintenance of bioreduced uranium may result from many factors including U(VI) sorption to iron-containing mineral phases, generation of H2S or FeS0.9, or the preferential sorption of U(VI) by microbial cells or biopolymers, but the processes controlling the reduction and in situ reoxidation rates are not known. To investigate the role of microbial community composition in the maintenance of bioreduced uranium, in-well sediment incubators (ISIs) were developed allowing field deployment of amended and native sediments during on-going experiments at the site. Field deployment of the ISIs allows expedient interrogation of microbial community response to field environmental perturbations and varying geochemical conditions.

  8. Does electrical stimulation reduce spasticity after stroke? A randomized controlled study.

    Science.gov (United States)

    Bakhtiary, Amir H; Fatemy, Elham

    2008-05-01

    To investigate the therapeutic effect of electrical stimulation on plantarflexor spasticity in stroke patients. A randomized controlled clinical trial study. Rehabilitation clinic of Semnan University of Medical Sciences. Forty stroke patients (aged from 42 to 65 years) with ankle plantarflexor spasticity. Fifteen minutes of inhibitory Bobath techniques were applied to one experimental group and a combination of 9 minutes of electrical stimulation on the dorsiflexor muscles and inhibitory Bobath techniques was applied to another group for 20 sessions daily. Passive ankle joint dorsiflexion range of motion, dorsiflexion strength test, plantarflexor muscle tone by Modified Ashworth Scale and soleus muscle H-reflex. The mean change of passive ankle joint dorsiflexion in the combination therapy group was 11.4 (SD 4.79) degrees versus 6.1 (SD 3.09) degrees, which was significantly higher (P = 0.001). The mean change of plantarflexor muscle tonicity measured by the Modified Ashworth Scale in the combination therapy group was -1.6 (SD 0.5) versus -1.1 (SD 0.31) in the Bobath group (P = 0.001). Dorsiflexor muscle strength was also increased significantly (P = 0.04) in the combination therapy group (0.7 +/- 0.37) compared with the Bobath group (0.4 +/- 0.23). However, no significant change in the amplitude of H-reflex was found between combination therapy (-0.41 +/- 0.29) and Bobath (-0.3 +/- 0.28) groups. Therapy combining Bobath inhibitory technique and electrical stimulation may help to reduce spasticity effectively in stroke patients.

  9. What potential has tobacco control for reducing health inequalities? The New Zealand situation

    Directory of Open Access Journals (Sweden)

    Blakely Tony

    2006-11-01

    Full Text Available Abstract In this Commentary, we aim to synthesize recent epidemiological data on tobacco and health inequalities for New Zealand and present it in new ways. We also aim to describe both existing and potential tobacco control responses for addressing these inequalities. In New Zealand smoking prevalence is higher amongst Māori and Pacific peoples (compared to those of "New Zealand European" ethnicity and amongst those with low socioeconomic position (SEP. Consequently the smoking-related mortality burden is higher among these populations. Regarding the gap in mortality between low and high socioeconomic groups, 21% and 11% of this gap for men and women was estimated to be due to smoking in 1996–99. Regarding the gap in mortality between Māori and non-Māori/non-Pacific, 5% and 8% of this gap for men and women was estimated to be due to smoking. The estimates from both these studies are probably moderate underestimates due to misclassification bias of smoking status. Despite the modest relative contribution of smoking to these gaps, the absolute number of smoking-attributable deaths is sizable and amenable to policy and health sector responses. There is some evidence, from New Zealand and elsewhere, for interventions that reduce smoking by low-income populations and indigenous peoples. These include tobacco taxation, thematically appropriate mass media campaigns, and appropriate smoking cessation support services. But there are as yet untried interventions with major potential. A key one is for a tighter regulatory framework that could rapidly shift the nicotine market towards pharmaceutical-grade nicotine (or smokeless tobacco products and away from smoked tobacco.

  10. Intravenous Vitamin C administration reduces fatigue in office workers: a double-blind randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Suh Sang-Yeon

    2012-01-01

    Full Text Available Abstract Background Studies of the efficacy of vitamin C treatment for fatigue have yielded inconsistent results. One of the reasons for this inconsistency could be the difference in delivery routes. Therefore, we planned a clinical trial with intravenous vitamin C administration. Methods We evaluated the effect of intravenous vitamin C on fatigue in office workers. A group of 141 healthy volunteers, aged 20 to 49 years participated in this randomized, double-blind, controlled clinical trial. The trial group received 10 grams of vitamin C with normal saline intravenously, while the placebo group received normal saline only. Since vitamin C is a well-known antioxidant, oxidative stress was measured. Fatigue score, oxidative stress, and plasma vitamin C levels were measured before intervention, and again two hours and one day after intervention. Adverse events were monitored. Results The fatigue scores measured at two hours after intervention and one day after intervention were significantly different between the two groups (p = 0.004; fatigue scores decreased in the vitamin C group after two hours and remained lower for one day. Trial also led to higher plasma vitamin C levels and lower oxidative stress compared to the placebo group (p Conclusion Thus, intravenous vitamin C reduced fatigue at two hours, and the effect persisted for one day. There were no significant differences in adverse events between two groups. High dose intravenous vitamin C proved to be safe and effective against fatigue in this study. Trial Registration The clinical trial registration of this trial is http://ClinicalTrials.govNCT00633581.

  11. Randomized controlled trial of topical EMLA and breastfeeding for reducing pain during wDPT vaccination.

    Science.gov (United States)

    Gupta, Navratan Kumar; Upadhyay, Amit; Agarwal, Astha; Goswami, Gaurav; Kumar, Jagdish; Sreenivas, V

    2013-11-01

    The primary objective was to evaluate the analgesic effect of a eutectic mixture of local anesthetics (EMLA) during whole cell DPT vaccination. The secondary objective was to evaluate if the analgesic effect of EMLA was synergistic to breastfeeding. A randomized, placebo-controlled trial was done to include infants of up to 3 months of age who came for their first DPT vaccination. The outcome variables were duration of cry, latency of onset of cry, and Modified Facial Coding Score. Thirty babies were enrolled in each of three groups. The groups did not differ significantly in baseline characteristics. Median (interquartile range) of duration of cry was least [34.6 (24.1-72.2) s] in babies receiving EMLA cream with breastfeeding (EB group), followed by 94.2 (46.1-180) s in babies receiving EMLA cream with oral distilled water (EW group), as compared to 180.0 (180-180) s in babies receiving placebo cream with oral distilled water (PCW group) (p cry was significantly greater in EB group [2.4 (1.14) s] and EW group [1.9 (0.62) s] as compared to babies in PCW group [1.5 (0.47) s] (p < 0.05), but the difference between EB and EW groups was not significant. Modified Facial Coding Score was significantly lower in EB group as compared to the other groups (p < 0.05). Topical EMLA is effective in reducing pain and has a synergistic effect in analgesia when combined with breastfeeding during vaccination in infants.

  12. Nonlinear Development and Secondary Instability of Traveling Crossflow Vortices

    Science.gov (United States)

    Li, Fei; Choudhari, Meelan M.; Duan, Lian; Chang, Chau-Lyan

    2014-01-01

    Transition research under NASA's Aeronautical Sciences Project seeks to develop a validated set of variable fidelity prediction tools with known strengths and limitations, so as to enable "sufficiently" accurate transition prediction and practical transition control for future vehicle concepts. This paper builds upon prior effort targeting the laminar breakdown mechanisms associated with stationary crossflow instability over a swept-wing configuration relevant to subsonic aircraft with laminar flow technology. Specifically, transition via secondary instability of traveling crossflow modes is investigated as an alternate scenario for transition. Results show that, for the parameter range investigated herein, secondary instability of traveling crossflow modes becomes insignificant in relation to the secondary instability of the stationary modes when the relative initial amplitudes of the traveling crossflow instability are lower than those of the stationary modes by approximately two orders of magnitudes or more. Linear growth predictions based on the secondary instability theory are found to agree well with those based on PSE and DNS, with the most significant discrepancies being limited to spatial regions of relatively weak secondary growth, i.e., regions where the primary disturbance amplitudes are smaller in comparison to its peak amplitude. Nonlinear effects on secondary instability evolution is also investigated and found to be initially stabilizing, prior to breakdown.

  13. Control valves and how to prevent them being the cause of process instability; Wie man verhindert, dass Regelventile die Ursache von Prozess-Instabilitaet werden

    Energy Technology Data Exchange (ETDEWEB)

    Grund, Tobias [Emerson Process Management GmbH und Co. OHG, Haan (Germany)

    2009-12-15

    Plant engineers and engineering managers often preside over departments that have responsibility for improving plant efficiency or availability, cutting raw material and utilities usage, or any one of a number of other Key Performance Indicators (KPIs) that are associated with the process automation equipment. In order to bring about these changes, investments are often made in the ''glamorous'' end of the business - the latest all digital control system, the newest and best advanced process control software, even higher accuracy measurement devices. This is all well and good providing the one component in the loop that moves, the control valve, is up to the job. Often overlooked, the valve has the ability to make or break any process automation investment. In this article a proven three step process is described that ensures the control valve will help reaching the achieved goals. (orig.)

  14. Taylor Instability of Incompressible Liquids

    Science.gov (United States)

    Fermi, E.; von Neumann, J.

    1955-11-01

    A discussion is presented in simplified form of the problem of the growth of an initial ripple on the surface of an incompressible liquid in the presence of an acceleration, g, directed from the outside into the liquid. The model is that of a heavy liquid occupying at t = 0 the half space above the plane z = 0, and a rectangular wave profile is assumed. The theory is found to represent correctly one feature of experimental results, namely the fact that the half wave of the heavy liquid into the vacuum becomes rapidly narrower while the half wave pushing into the heavy liquid becomes more and more blunt. The theory fails to account for the experimental results according to which the front of the wave pushing into the heavy liquid moves with constant velocity. The case of instability at the boundary of 2 fluids of different densities is also explored. Similar results are obtained except that the acceleration of the heavy liquid into the light liquid is reduced.

  15. Analysis of beam transverse instability in electron linac

    International Nuclear Information System (INIS)

    Mondrus, I.N.; Shenderovich, A.M.

    1990-01-01

    Dispersion equations describing transverse beam instability in a single resonator section and in an accelerator comprising a sequence of resonator sections are derived. It is shown that close to parametric resonance of any multiplicity a reduction of cumulative instability incoherent takes place between nonsymmetric defocusing wave frequency and the frequency of accelerator cluster transport. Under exact resonance the increment equals to zero and under misalignment due to resonance depending on its sign and disturbance frequency an instability of either fast or slow wave takes place. It is shown that this effect leads to beam instability suppression of sections with the opposite sign of misalignment due to resonance are located in turn. The results obtained show that application of a parametric resonance through reducing slight the single section absolute instability threshold current, allows one to effectively suppress cumulative instability. The requirement to the accuracy of tuning to a resonance of identical sections is substantially reduced under the alternation of sections with different sign misalignment due to resonance and can be easily realized in practice

  16. Obsessive-compulsive Disorder patients have a reduced sense of control on the illusion of control task

    Directory of Open Access Journals (Sweden)

    Claire Marie Gillan

    2014-03-01

    Full Text Available There is disagreement regarding then role of perceived control in obsessive-compulsive disorder (OCD. The present study used a traditional illusion of control paradigm (Alloy & Abramson, 1979 to empirically test control estimation in OCD. Twenty-six OCD patients and 26 matched comparison subjects completed an illusion of control task wherein their goal was to attempt to exert control over a light bulb. The density of reinforcement (high, low and the valence of trials (gain, loss were experimentally manipulated within subjects. Unbeknownst to participants, the illumination of the light bulb was predetermined and irrespective of their behavior. OCD patients exhibited lower estimates of control compared with healthy comparison subjects. There were no interactions between group and outcome density or group and valence. We found that OCD patients endorse lower estimates of control than comparison subjects. This finding highlights a potential role for contingency learning in the disorder.

  17. Testing a simple control law to reduce broadband frequency harmonic vibrations using semi-active tuned mass dampers

    International Nuclear Information System (INIS)

    Moutinho, Carlos

    2015-01-01

    This paper is focused on the control problems related to semi-active tuned mass dampers (TMDs) used to reduce harmonic vibrations, specially involving civil structures. A simplified version of the phase control law is derived and its effectiveness is investigated and evaluated. The objective is to improve the functioning of control systems of this type by simplifying the measurement process and reducing the number of variables involved, making the control system more feasible and reliable. Because the control law is of ON/OFF type, combined with appropriate trigger conditions, the activity of the actuation system may be significantly reduced, which may be of few seconds a day in many practical cases, increasing the durability of the device and reducing its maintenance. Moreover, due to the ability of the control system to command the motion of the inertial mass, the semi-active TMD is relatively insensitive to its initial tuning, resulting in the capability of self-tuning and in the possibility of controlling several vibration modes of a structure over a significant broadband frequency. (paper)

  18. Size effects on cavitation instabilities

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Tvergaard, Viggo

    2006-01-01

    growth is here analyzed for such cases. A finite strain generalization of a higher order strain gradient plasticity theory is applied for a power-law hardening material, and the numerical analyses are carried out for an axisymmetric unit cell containing a spherical void. In the range of high stress...... triaxiality, where cavitation instabilities are predicted by conventional plasticity theory, such instabilities are also found for the nonlocal theory, but the effects of gradient hardening delay the onset of the instability. Furthermore, in some cases the cavitation stress reaches a maximum and then decays...... as the void grows to a size well above the characteristic material length....

  19. Resistive instabilities in tokamaks

    International Nuclear Information System (INIS)

    Rutherford, P.H.

    1985-10-01

    Low-m tearing modes constitute the dominant instability problem in present-day tokamaks. In this lecture, the stability criteria for representative current profiles with q(0)-values slightly less than unit are reviewed; ''sawtooth'' reconnection to q(0)-values just at, or slightly exceeding, unity is generally destabilizing to the m = 2, n = 1 and m = 3, n = 2 modes, and severely limits the range of stable profile shapes. Feedback stabilization of m greater than or equal to 2 modes by rf heating or current drive, applied locally at the magnetic islands, appears feasible; feedback by island current drive is much more efficient, in terms of the radio-frequency power required, then feedback by island heating. Feedback stabilization of the m = 1 mode - although yielding particularly beneficial effects for resistive-tearing and high-beta stability by allowing q(0)-values substantially below unity - is more problematical, unless the m = 1 ideal-MHD mode can be made positively stable by strong triangular shaping of the central flux surfaces. Feedback techniques require a detectable, rotating MHD-like signal; the slowing of mode rotation - or the excitation of non-rotating modes - by an imperfectly conducting wall is also discussed

  20. Sheared Electroconvective Instability

    Science.gov (United States)

    Kwak, Rhokyun; Pham, Van Sang; Lim, Kiang Meng; Han, Jongyoon

    2012-11-01

    Recently, ion concentration polarization (ICP) and related phenomena draw attention from physicists, due to its importance in understanding electrochemical systems. Researchers have been actively studying, but the complexity of this multiscale, multiphysics phenomenon has been limitation for gaining a detailed picture. Here, we consider electroconvective(EC) instability initiated by ICP under pressure-driven flow, a scenario often found in electrochemical desalinations. Combining scaling analysis, experiment, and numerical modeling, we reveal unique behaviors of sheared EC: unidirectional vortex structures, its size selection and vortex propagation. Selected by balancing the external pressure gradient and the electric body force, which generates Hagen-Poiseuille(HP) flow and vortical EC, the dimensionless EC thickness scales as (φ2 /UHP)1/3. The pressure-driven flow(or shear) suppresses unfavorably-directed vortices, and simultaneously pushes favorably-directed vortices with constant speed, which is linearly proportional to the total shear of HP flow. This is the first systematic characterization of sheared EC, which has significant implications on the optimization of electrodialysis and other electrochemical systems.

  1. Water level measurement uncertainty during BWR instability

    International Nuclear Information System (INIS)

    Torok, R.C.; Derbidge, T.C.; Healzer, J.M.

    1994-01-01

    This paper addresses the performance of the water-level measurement system in a boiling water reactor (BWR) during severe instability oscillations which, under some circumstances, can occur during an anticipated transient without SCRAM (ATWS). Test data from a prototypical mock-up of the water-level measurement system was used to refine and calibrate a water-level measurement system model. The model was then used to predict level measurement system response, using as boundary conditions vessel pressures calculated by ppercase RETRAN for an ATWS/instability event.The results of the study indicate that rapid pressure changes in the reactor pressure vessel which cause oscillations in downcomer water level, coupled with differences in instrument line lengths, can produce errors in the sensed water level. Using nominal parameters for the measurement system components, a severe instability transient which produced a 0.2 m peak-to-minimum water-level oscillation in the vessel downcomer was predicted to produce pressure difference equivalent to a 0.7 m level oscillation at the input to the differential pressure transmitter, 0.5 m oscillation at the output of the transmitter, and an oscillation of 0.3 m on the water-level indicator in the control room. The level measurement system error, caused by downcomer water-level oscillations and instrument line length differential, is mitigated by damping both in the differential pressure transmitter used to infer level and in the control room display instrument. ((orig.))

  2. Selected Topics in Microwave Instabilities and Linacs

    Energy Technology Data Exchange (ETDEWEB)

    Ng, K. Y. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2013-06-01

    The Shanghai Institute of Applied Physics (SINAP) is embarking on its first X-ray free-electron laser (FEL) project. It is a cascading high-gain harmonic generation FEL. Microwave instabilities driven by various effects, especially the space-charge force, will degrade the qual- ity of the electron beam before entering into the undulator. However, inside the undulator, the occurrence of microbunching becomes an ut- most important ingredient for the generation of coherent radiation. In short, controlled and uncontrolled microwave instabilities must be fully understood in such a project. These are the slides of a series of eight-hour lectures given at the SINAP in June of 2013, with the intention of a fully understanding of the microbunching phenomenon. The sections of wake field and impedance theory are added as an in- troduction for those who are not familiar with the subject.

  3. Tranexamic acid reduces blood loss during and after cesarean section: A double blinded, randomized, controlled trial

    Directory of Open Access Journals (Sweden)

    Amr H. Yehia

    2014-03-01

    Conclusions: Tranexamic acid can be used safely to reduce blood loss during cesarean section. Reduced blood loss after tranexamic acid was associated with improvement of post-operative hemoglobin, hematocrit and with reduction of post-partum need for iron replacement.

  4. Changing Workplaces to Reduce Work-Family Conflict: Schedule Control in a White-Collar Organization

    Science.gov (United States)

    Kelly, Erin L.; Moen, Phyllis; Tranby, Eric

    2011-01-01

    Work-family conflicts are common and consequential for employees, their families, and work organizations. Can workplaces be changed to reduce work-family conflict? Previous research has not been able to assess whether workplace policies or initiatives succeed in reducing work-family conflict or increasing work-family fit. Using longitudinal data…

  5. Tunnelling instability via perturbation theory

    Energy Technology Data Exchange (ETDEWEB)

    Graffi, S. (Bologna Univ. (Italy). Dip. di Matematica); Grecchi, V. (Moderna Univ. (Italy). Dip. di Matematica); Jona-Lasinio, G. (Paris-11 Univ., 91 - Orsay (France). Lab. de Physique Theorique et Hautes Energies)

    1984-10-21

    The semiclassical limit of low lying states in a multiwell potential is studied by rigorous perturbative techniques. In particular tunnelling instability and localisation of wave functions is obtained in a simple way under small deformations of symmetric potentials.

  6. Fluctuations and Instability in Sedimentation

    KAUST Repository

    Guazzelli, É lisabeth; Hinch, John

    2011-01-01

    This review concentrates on the fluctuations of the velocities of sedimenting spheres, and on the structural instability of a suspension of settling fibers. For many years, theoretical estimates and numerical simulations predicted the fluctuations

  7. Edge instabilities of topological superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, Johannes S. [Institut fuer Theoretische Physik und Astrophysik, Universitaet Wuerzburg (Germany); Max-Planck-Institut fuer Festkoerperforschung, Stuttgart (Germany); Assaad, Fakher F. [Institut fuer Theoretische Physik und Astrophysik, Universitaet Wuerzburg (Germany); Schnyder, Andreas P. [Max-Planck-Institut fuer Festkoerperforschung, Stuttgart (Germany)

    2016-07-01

    Nodal topological superconductors display zero-energy Majorana flat bands at generic edges. The flatness of these edge bands, which is protected by time-reversal and translation symmetry, gives rise to an extensive ground state degeneracy and a diverging density of states. Therefore, even arbitrarily weak interactions lead to an instability of the flat-band edge states towards time-reversal and translation-symmetry broken phases, which lift the ground-state degeneracy. Here, we employ Monte Carlo simulations combined with mean-field considerations to examine the instabilities of the flat-band edge states of d{sub xy}-wave superconductors. We find that attractive interactions induce a complex s-wave pairing instability together with a density wave instability. Repulsive interactions, on the other hand, lead to ferromagnetism mixed with spin-triplet pairing at the edge. We discuss the implications of our findings for experiments on cuprate high-temperature superconductors.

  8. Instability of ties in compression

    DEFF Research Database (Denmark)

    Buch-Hansen, Thomas Cornelius

    2013-01-01

    Masonry cavity walls are loaded by wind pressure and vertical load from upper floors. These loads results in bending moments and compression forces in the ties connecting the outer and the inner wall in a cavity wall. Large cavity walls are furthermore loaded by differential movements from...... the temperature gradient between the outer and the inner wall, which results in critical increase of the bending moments in the ties. Since the ties are loaded by combined compression and moment forces, the loadbearing capacity is derived from instability equilibrium equations. Most of them are iterative, since...... exact instability solutions are complex to derive, not to mention the extra complexity introducing dimensional instability from the temperature gradients. Using an inverse variable substitution and comparing an exact theory with an analytical instability solution a method to design tie...

  9. Summary of longitudinal instabilities workshop

    Energy Technology Data Exchange (ETDEWEB)

    Chasman, R.

    1976-01-01

    A five-day ISABELLE workshop on longitudinal instabilities was held at Brookhaven, August 9-13, 1976. About a dozen outside accelerator experts, both from Europe and the U.S.A., joined the local staff for discussions of longitudinal instabilities in ISABELLE. An agenda of talks was scheduled for the first day of the workshop. Later during the week, a presentation was given on the subject ''A more rigorous treatment of Landau damping in longitudinal beam instabilities''. A few progress meetings were held in which disagreements regarding calculations of coupling impedances were clarified. A summary session was held on the last day. Heavy emphasis was put on single bunched beam instabilities in the microwave region extending above the cut-off frequency of the ISABELLE vacuum chamber.

  10. WELLBORE INSTABILITY: CAUSES AND CONSEQUENCES

    Directory of Open Access Journals (Sweden)

    Borivoje Pašić

    2007-12-01

    Full Text Available Wellbore instability is one of the main problems that engineers meet during drilling. The causes of wellbore instability are often classified into either mechanical (for example, failure of the rock around the hole because of high stresses, low rock strength, or inappropriate drilling practice or chemical effects which arise from damaging interaction between the rock, generally shale, and the drilling fluid. Often, field instances of instability are a result of a combination of both chemical and mechanical. This problem might cause serious complication in well and in some case can lead to expensive operational problems. The increasing demand for wellbore stability analyses during the planning stage of a field arise from economic considerations and the increasing use of deviated, extended reach and horizontal wells. This paper presents causes, indicators and diagnosing of wellbore instability as well as the wellbore stresses model.

  11. CPG-Based Locomotion Control of a Robotic Fish : Using Linear Oscillators and Reducing Control Parameters via PSO

    NARCIS (Netherlands)

    Wang, Chen; Xie, G.; Wang, L.; Cao, M.

    The aim of the present study is to investigate the locomotion control of a robotic fish. To achieve this goal, we design a control architecture based on a novel central pattern generator (CPG) and implement it as a system of coupled linear oscillators. This design differs significantly from the

  12. Are the Kinematics of the Knee Joint Altered during the Loading Response Phase of Gait in Individuals with Concurrent Knee Osteoarthritis and Complaints of Joint Instability? A Dynamic Stereo X-ray Study

    Science.gov (United States)

    Farrokhi, Shawn; Tashman, Scott; Gil, Alexandra B.; Klatt, Brian A.; Fitzgerald, G. Kelley

    2011-01-01

    Background Joint instability has been suggested as a risk factor for knee osteoarthritis and a cause of significant functional declines in those with symptomatic disease. However, the relationship between altered knee joint mechanics and self-reports of instability in individuals with knee osteoarthritis remains unclear. Methods Fourteen subjects with knee osteoarthritis and complaints of joint instability and 12 control volunteers with no history of knee disease were recruited for this study. Dynamic stereo X-ray technology was used to assess the three-dimensional kinematics of the knee joint during the loading response phase of gait. Findings Individuals with concurrent knee osteoarthritis and joint instability demonstrated significantly reduced flexion and internal/external rotation knee motion excursions during the loading response phase of gait (P knee joint at initial contact was significantly different (P knee osteoarthritis and joint instability. However, the anteroposterior and mediolateral tibiofemoral joint positions at initial contact and the corresponding total joint translations were similar between groups during the loading phase of gait. Interpretations The rotational patterns of tibiofemoral joint motion and joint alignments reported for individuals with concurrent knee osteoarthritis and joint instability are consistent with those previously established for individuals with knee osteoarthritis. Furthermore, the findings of similar translatory tibiofemoral motion between groups suggest that self-reports of episodic joint instability in individuals with knee osteoarthritis may not necessarily be associated with adaptive alterations in joint arthrokinematics. PMID:22071429

  13. Are the kinematics of the knee joint altered during the loading response phase of gait in individuals with concurrent knee osteoarthritis and complaints of joint instability? A dynamic stereo X-ray study.

    Science.gov (United States)

    Farrokhi, Shawn; Tashman, Scott; Gil, Alexandra B; Klatt, Brian A; Fitzgerald, G Kelley

    2012-05-01

    Joint instability has been suggested as a risk factor for knee osteoarthritis and a cause of significant functional decline in those with symptomatic disease. However, the relationship between altered knee joint mechanics and self-reports of instability in individuals with knee osteoarthritis remains unclear. Fourteen subjects with knee osteoarthritis and complaints of joint instability and 12 control volunteers with no history of knee disease were recruited for this study. Dynamic stereo X-ray technology was used to assess the three-dimensional kinematics of the knee joint during the loading response phase of gait. Individuals with concurrent knee osteoarthritis and joint instability demonstrated significantly reduced flexion and internal/external rotation knee motion excursions during the loading response phase of gait (Pknee joint at initial contact was significantly different (Pknee osteoarthritis and joint instability. However, the anteroposterior and mediolateral tibiofemoral joint positions at initial contact and the corresponding total joint translations were similar between groups during the loading phase of gait. The rotational patterns of tibiofemoral joint motion and joint alignments reported for individuals with concurrent knee osteoarthritis and joint instability are consistent with those previously established for individuals with knee osteoarthritis. Furthermore, the findings of similar translatory tibiofemoral motion between groups suggest that self-reports of episodic joint instability in individuals with knee osteoarthritis may not necessarily be associated with adaptive alterations in joint arthrokinematics. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. Genomic instability and radiation effects

    International Nuclear Information System (INIS)

    Christian Streffer

    2007-01-01

    Complete text of publication follows. Cancer, genetic mutations and developmental abnormalities are apparently associated with an increased genomic instability. Such phenomena have been frequently shown in human cancer cells in vitro and in situ. It is also well-known that individuals with a genetic predisposition for cancer proneness, such as ataxia telangiectesia, Fanconi anaemia etc. demonstrate a general high genomic instability e.g. in peripheral lymphocytes before a cancer has developed. Analogous data have been found in mice which develop a specific congenital malformation which has a genetic background. Under these aspects it is of high interest that ionising radiation can increase the genomic instability of mammalian cells after exposures in vitro an in vivo. This phenomenon is expressed 20 to 40 cell cycles after the exposure e.g. by de novo chromosomal aberrations. Such effects have been observed with high and low LET radiation, high LET radiation is more efficient. With low LET radiation a good dose response is observed in the dose range 0.2 to 2.0 Gy, Recently it has been reported that senescence and genomic instability was induced in human fibroblasts after 1 mGy carbon ions (1 in 18 cells are hit), apparently bystander effects also occurred under these conditions. The instability has been shown with DNA damage, chromosomal aberrations, gene mutation and cell death. It is also transferred to the next generation of mice with respect to gene mutations, chromosomal aberrations and congenital malformations. Several mechanisms have been discussed. The involvement of telomeres has gained interest. Genomic instability seems to be induced by a general lesion to the whole genome. The transmission of one chromosome from an irradiated cell to an non-irradiated cell leads to genomic instability in the untreated cells. Genomic instability increases mutation rates in the affected cells in general. As radiation late effects (cancer, gene mutations and congenital